Add __attribute__ ((tainted_args))
This patch adds a new __attribute__ ((tainted_args)) to the C/C++ frontends.
It can be used on function decls: the analyzer will treat as tainted
all parameters to the function and all buffers pointed to by parameters
to the function. Adding this in one place to the Linux kernel's
__SYSCALL_DEFINEx macro allows the analyzer to treat all syscalls as
having tainted inputs. This gives some coverage of system calls without
needing to "teach" the analyzer about "__user" - an example of the use
of this can be seen in CVE-2011-2210, where given:
SYSCALL_DEFINE5(osf_getsysinfo, unsigned long, op, void __user *, buffer,
unsigned long, nbytes, int __user *, start, void __user *, arg)
the analyzer will treat the nbytes param as under attacker control, and
can complain accordingly:
taint-CVE-2011-2210-1.c: In function 'sys_osf_getsysinfo':
taint-CVE-2011-2210-1.c:69:21: warning: use of attacker-controlled value
'nbytes' as size without upper-bounds checking [CWE-129] [-Wanalyzer-tainted-size]
69 | if (copy_to_user(buffer, hwrpb, nbytes) != 0)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Additionally, the patch allows the attribute to be used on field decls:
specifically function pointers. Any function used as an initializer
for such a field gets treated as being called with tainted arguments.
An example can be seen in CVE-2020-13143, where adding
__attribute__((tainted_args)) to the "store" callback of
configfs_attribute:
struct configfs_attribute {
/* [...snip...] */
ssize_t (*store)(struct config_item *, const char *, size_t)
__attribute__((tainted_args));
/* [...snip...] */
};
allows the analyzer to see:
CONFIGFS_ATTR(gadget_dev_desc_, UDC);
and treat gadget_dev_desc_UDC_store as having tainted arguments, so that
it complains:
taint-CVE-2020-13143-1.c: In function 'gadget_dev_desc_UDC_store':
taint-CVE-2020-13143-1.c:33:17: warning: use of attacker-controlled value
'len + 18446744073709551615' as offset without upper-bounds checking [CWE-823] [-Wanalyzer-tainted-offset]
33 | if (name[len - 1] == '\n')
| ~~~~^~~~~~~~~
As before this currently still needs -fanalyzer-checker=taint (in
addition to -fanalyzer).
gcc/analyzer/ChangeLog:
* engine.cc: Include "stringpool.h", "attribs.h", and
"tree-dfa.h".
(mark_params_as_tainted): New.
(class tainted_args_function_custom_event): New.
(class tainted_args_function_info): New.
(exploded_graph::add_function_entry): Handle functions with
"tainted_args" attribute.
(class tainted_args_field_custom_event): New.
(class tainted_args_callback_custom_event): New.
(class tainted_args_call_info): New.
(add_tainted_args_callback): New.
(add_any_callbacks): New.
(exploded_graph::build_initial_worklist): Likewise.
(exploded_graph::build_initial_worklist): Find callbacks that are
reachable from global initializers, calling add_any_callbacks on
them.
gcc/c-family/ChangeLog:
* c-attribs.c (c_common_attribute_table): Add "tainted_args".
(handle_tainted_args_attribute): New.
gcc/ChangeLog:
* doc/extend.texi (Function Attributes): Note that "tainted_args" can
be used on field decls.
(Common Function Attributes): Add entry on "tainted_args" attribute.
gcc/testsuite/ChangeLog:
* gcc.dg/analyzer/attr-tainted_args-1.c: New test.
* gcc.dg/analyzer/attr-tainted_args-misuses.c: New test.
* gcc.dg/analyzer/taint-CVE-2011-2210-1.c: New test.
* gcc.dg/analyzer/taint-CVE-2020-13143-1.c: New test.
* gcc.dg/analyzer/taint-CVE-2020-13143-2.c: New test.
* gcc.dg/analyzer/taint-CVE-2020-13143.h: New test.
* gcc.dg/analyzer/taint-alloc-3.c: New test.
* gcc.dg/analyzer/taint-alloc-4.c: New test.
* gcc.dg/analyzer/test-uaccess.h: New test.
Signed-off-by: David Malcolm <dmalcolm@redhat.com>
This commit is contained in:
David Malcolm
parent
ad3f0d0806
commit
b31cec9c22
@ -68,6 +68,9 @@ along with GCC; see the file COPYING3. If not see
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#include "plugin.h"
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#include "target.h"
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#include <memory>
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#include "stringpool.h"
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#include "attribs.h"
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#include "tree-dfa.h"
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/* For an overview, see gcc/doc/analyzer.texi. */
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@ -2287,6 +2290,116 @@ exploded_graph::~exploded_graph ()
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delete (*iter).second;
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}
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/* Subroutine for use when implementing __attribute__((tainted_args))
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on functions and on function pointer fields in structs.
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Called on STATE representing a call to FNDECL.
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Mark all params of FNDECL in STATE as "tainted". Mark the value of all
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regions pointed to by params of FNDECL as "tainted".
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Return true if successful; return false if the "taint" state machine
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was not found. */
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static bool
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mark_params_as_tainted (program_state *state, tree fndecl,
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const extrinsic_state &ext_state)
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{
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unsigned taint_sm_idx;
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if (!ext_state.get_sm_idx_by_name ("taint", &taint_sm_idx))
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return false;
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sm_state_map *smap = state->m_checker_states[taint_sm_idx];
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const state_machine &sm = ext_state.get_sm (taint_sm_idx);
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state_machine::state_t tainted = sm.get_state_by_name ("tainted");
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region_model_manager *mgr = ext_state.get_model_manager ();
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function *fun = DECL_STRUCT_FUNCTION (fndecl);
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gcc_assert (fun);
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for (tree iter_parm = DECL_ARGUMENTS (fndecl); iter_parm;
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iter_parm = DECL_CHAIN (iter_parm))
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{
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tree param = iter_parm;
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if (tree parm_default_ssa = ssa_default_def (fun, iter_parm))
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param = parm_default_ssa;
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const region *param_reg = state->m_region_model->get_lvalue (param, NULL);
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const svalue *init_sval = mgr->get_or_create_initial_value (param_reg);
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smap->set_state (state->m_region_model, init_sval,
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tainted, NULL /*origin_new_sval*/, ext_state);
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if (POINTER_TYPE_P (TREE_TYPE (param)))
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{
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const region *pointee_reg = mgr->get_symbolic_region (init_sval);
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/* Mark "*param" as tainted. */
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const svalue *init_pointee_sval
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= mgr->get_or_create_initial_value (pointee_reg);
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smap->set_state (state->m_region_model, init_pointee_sval,
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tainted, NULL /*origin_new_sval*/, ext_state);
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}
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}
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return true;
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}
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/* Custom event for use by tainted_args_function_info when a function
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has been marked with __attribute__((tainted_args)). */
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class tainted_args_function_custom_event : public custom_event
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{
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public:
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tainted_args_function_custom_event (location_t loc, tree fndecl, int depth)
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: custom_event (loc, fndecl, depth),
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m_fndecl (fndecl)
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{
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}
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label_text get_desc (bool can_colorize) const FINAL OVERRIDE
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{
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return make_label_text
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(can_colorize,
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"function %qE marked with %<__attribute__((tainted_args))%>",
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m_fndecl);
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}
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private:
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tree m_fndecl;
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};
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/* Custom exploded_edge info for top-level calls to a function
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marked with __attribute__((tainted_args)). */
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class tainted_args_function_info : public custom_edge_info
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{
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public:
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tainted_args_function_info (tree fndecl)
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: m_fndecl (fndecl)
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{}
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void print (pretty_printer *pp) const FINAL OVERRIDE
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{
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pp_string (pp, "call to tainted_args function");
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};
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bool update_model (region_model *,
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const exploded_edge *,
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region_model_context *) const FINAL OVERRIDE
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{
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/* No-op. */
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return true;
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}
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void add_events_to_path (checker_path *emission_path,
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const exploded_edge &) const FINAL OVERRIDE
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{
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emission_path->add_event
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(new tainted_args_function_custom_event
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(DECL_SOURCE_LOCATION (m_fndecl), m_fndecl, 0));
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}
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private:
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tree m_fndecl;
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};
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/* Ensure that there is an exploded_node representing an external call to
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FUN, adding it to the worklist if creating it.
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@ -2313,14 +2426,25 @@ exploded_graph::add_function_entry (function *fun)
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program_state state (m_ext_state);
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state.push_frame (m_ext_state, fun);
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custom_edge_info *edge_info = NULL;
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if (lookup_attribute ("tainted_args", DECL_ATTRIBUTES (fun->decl)))
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{
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if (mark_params_as_tainted (&state, fun->decl, m_ext_state))
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edge_info = new tainted_args_function_info (fun->decl);
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}
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if (!state.m_valid)
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return NULL;
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exploded_node *enode = get_or_create_node (point, state, NULL);
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if (!enode)
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return NULL;
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{
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delete edge_info;
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return NULL;
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}
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add_edge (m_origin, enode, NULL);
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add_edge (m_origin, enode, NULL, edge_info);
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m_functions_with_enodes.add (fun);
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@ -2634,6 +2758,187 @@ toplevel_function_p (function *fun, logger *logger)
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return true;
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}
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/* Custom event for use by tainted_call_info when a callback field has been
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marked with __attribute__((tainted_args)), for labelling the field. */
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class tainted_args_field_custom_event : public custom_event
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{
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public:
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tainted_args_field_custom_event (tree field)
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: custom_event (DECL_SOURCE_LOCATION (field), NULL_TREE, 0),
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m_field (field)
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{
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}
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label_text get_desc (bool can_colorize) const FINAL OVERRIDE
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{
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return make_label_text (can_colorize,
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"field %qE of %qT"
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" is marked with %<__attribute__((tainted_args))%>",
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m_field, DECL_CONTEXT (m_field));
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}
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private:
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tree m_field;
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};
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/* Custom event for use by tainted_call_info when a callback field has been
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marked with __attribute__((tainted_args)), for labelling the function used
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in that callback. */
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class tainted_args_callback_custom_event : public custom_event
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{
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public:
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tainted_args_callback_custom_event (location_t loc, tree fndecl, int depth,
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tree field)
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: custom_event (loc, fndecl, depth),
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m_field (field)
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{
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}
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label_text get_desc (bool can_colorize) const FINAL OVERRIDE
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{
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return make_label_text (can_colorize,
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"function %qE used as initializer for field %qE"
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" marked with %<__attribute__((tainted_args))%>",
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m_fndecl, m_field);
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}
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private:
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tree m_field;
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};
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/* Custom edge info for use when adding a function used by a callback field
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marked with '__attribute__((tainted_args))'. */
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class tainted_args_call_info : public custom_edge_info
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{
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public:
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tainted_args_call_info (tree field, tree fndecl, location_t loc)
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: m_field (field), m_fndecl (fndecl), m_loc (loc)
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{}
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void print (pretty_printer *pp) const FINAL OVERRIDE
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{
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pp_string (pp, "call to tainted field");
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};
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bool update_model (region_model *,
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const exploded_edge *,
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region_model_context *) const FINAL OVERRIDE
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{
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/* No-op. */
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return true;
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}
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void add_events_to_path (checker_path *emission_path,
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const exploded_edge &) const FINAL OVERRIDE
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{
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/* Show the field in the struct declaration, e.g.
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"(1) field 'store' is marked with '__attribute__((tainted_args))'" */
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emission_path->add_event
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(new tainted_args_field_custom_event (m_field));
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/* Show the callback in the initializer
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e.g.
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"(2) function 'gadget_dev_desc_UDC_store' used as initializer
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for field 'store' marked with '__attribute__((tainted_args))'". */
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emission_path->add_event
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(new tainted_args_callback_custom_event (m_loc, m_fndecl, 0, m_field));
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}
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private:
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tree m_field;
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tree m_fndecl;
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location_t m_loc;
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};
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/* Given an initializer at LOC for FIELD marked with
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'__attribute__((tainted_args))' initialized with FNDECL, add an
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entrypoint to FNDECL to EG (and to its worklist) where the params to
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FNDECL are marked as tainted. */
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static void
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add_tainted_args_callback (exploded_graph *eg, tree field, tree fndecl,
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location_t loc)
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{
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logger *logger = eg->get_logger ();
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LOG_SCOPE (logger);
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if (!gimple_has_body_p (fndecl))
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return;
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const extrinsic_state &ext_state = eg->get_ext_state ();
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function *fun = DECL_STRUCT_FUNCTION (fndecl);
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gcc_assert (fun);
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program_point point
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= program_point::from_function_entry (eg->get_supergraph (), fun);
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program_state state (ext_state);
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state.push_frame (ext_state, fun);
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if (!mark_params_as_tainted (&state, fndecl, ext_state))
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return;
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if (!state.m_valid)
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return;
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exploded_node *enode = eg->get_or_create_node (point, state, NULL);
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if (logger)
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{
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if (enode)
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logger->log ("created EN %i for tainted_args %qE entrypoint",
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enode->m_index, fndecl);
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else
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{
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logger->log ("did not create enode for tainted_args %qE entrypoint",
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fndecl);
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return;
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}
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}
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tainted_args_call_info *info
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= new tainted_args_call_info (field, fndecl, loc);
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eg->add_edge (eg->get_origin (), enode, NULL, info);
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}
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/* Callback for walk_tree for finding callbacks within initializers;
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ensure that any callback initializer where the corresponding field is
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marked with '__attribute__((tainted_args))' is treated as an entrypoint
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to the analysis, special-casing that the inputs to the callback are
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untrustworthy. */
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static tree
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add_any_callbacks (tree *tp, int *, void *data)
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{
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exploded_graph *eg = (exploded_graph *)data;
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if (TREE_CODE (*tp) == CONSTRUCTOR)
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{
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/* Find fields with the "tainted_args" attribute.
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walk_tree only walks the values, not the index values;
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look at the index values. */
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unsigned HOST_WIDE_INT idx;
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constructor_elt *ce;
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for (idx = 0; vec_safe_iterate (CONSTRUCTOR_ELTS (*tp), idx, &ce);
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idx++)
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if (ce->index && TREE_CODE (ce->index) == FIELD_DECL)
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if (lookup_attribute ("tainted_args", DECL_ATTRIBUTES (ce->index)))
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{
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tree value = ce->value;
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if (TREE_CODE (value) == ADDR_EXPR
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&& TREE_CODE (TREE_OPERAND (value, 0)) == FUNCTION_DECL)
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add_tainted_args_callback (eg, ce->index,
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TREE_OPERAND (value, 0),
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EXPR_LOCATION (value));
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}
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}
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return NULL_TREE;
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}
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/* Add initial nodes to EG, with entrypoints for externally-callable
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functions. */
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@ -2659,6 +2964,17 @@ exploded_graph::build_initial_worklist ()
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logger->log ("did not create enode for %qE entrypoint", fun->decl);
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}
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}
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/* Find callbacks that are reachable from global initializers. */
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varpool_node *vpnode;
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FOR_EACH_VARIABLE (vpnode)
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{
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tree decl = vpnode->decl;
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tree init = DECL_INITIAL (decl);
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if (!init)
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continue;
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walk_tree (&init, add_any_callbacks, this, NULL);
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}
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}
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/* The main loop of the analysis.
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@ -117,6 +117,7 @@ static tree handle_no_profile_instrument_function_attribute (tree *, tree,
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tree, int, bool *);
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static tree handle_malloc_attribute (tree *, tree, tree, int, bool *);
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static tree handle_dealloc_attribute (tree *, tree, tree, int, bool *);
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static tree handle_tainted_args_attribute (tree *, tree, tree, int, bool *);
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static tree handle_returns_twice_attribute (tree *, tree, tree, int, bool *);
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static tree handle_no_limit_stack_attribute (tree *, tree, tree, int,
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bool *);
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@ -548,6 +549,8 @@ const struct attribute_spec c_common_attribute_table[] =
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handle_objc_nullability_attribute, NULL },
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{ "*dealloc", 1, 2, true, false, false, false,
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handle_dealloc_attribute, NULL },
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{ "tainted_args", 0, 0, true, false, false, false,
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handle_tainted_args_attribute, NULL },
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{ NULL, 0, 0, false, false, false, false, NULL, NULL }
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};
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@ -5774,6 +5777,39 @@ handle_objc_nullability_attribute (tree *node, tree name, tree args,
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return NULL_TREE;
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}
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/* Handle a "tainted_args" attribute; arguments as in
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struct attribute_spec.handler. */
|
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static tree
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handle_tainted_args_attribute (tree *node, tree name, tree, int,
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bool *no_add_attrs)
|
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{
|
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if (TREE_CODE (*node) != FUNCTION_DECL
|
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&& TREE_CODE (*node) != FIELD_DECL)
|
||||
{
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warning (OPT_Wattributes, "%qE attribute ignored; valid only "
|
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"for functions and function pointer fields",
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name);
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*no_add_attrs = true;
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return NULL_TREE;
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}
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if (TREE_CODE (*node) == FIELD_DECL
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||||
&& !(TREE_CODE (TREE_TYPE (*node)) == POINTER_TYPE
|
||||
&& TREE_CODE (TREE_TYPE (TREE_TYPE (*node))) == FUNCTION_TYPE))
|
||||
{
|
||||
warning (OPT_Wattributes, "%qE attribute ignored;"
|
||||
" field must be a function pointer",
|
||||
name);
|
||||
*no_add_attrs = true;
|
||||
return NULL_TREE;
|
||||
}
|
||||
|
||||
*no_add_attrs = false; /* OK */
|
||||
|
||||
return NULL_TREE;
|
||||
}
|
||||
|
||||
/* Attempt to partially validate a single attribute ATTR as if
|
||||
it were to be applied to an entity OPER. */
|
||||
|
||||
|
||||
@ -2512,7 +2512,8 @@ variable declarations (@pxref{Variable Attributes}),
|
||||
labels (@pxref{Label Attributes}),
|
||||
enumerators (@pxref{Enumerator Attributes}),
|
||||
statements (@pxref{Statement Attributes}),
|
||||
and types (@pxref{Type Attributes}).
|
||||
types (@pxref{Type Attributes}),
|
||||
and on field declarations (for @code{tainted_args}).
|
||||
|
||||
There is some overlap between the purposes of attributes and pragmas
|
||||
(@pxref{Pragmas,,Pragmas Accepted by GCC}). It has been
|
||||
@ -4009,6 +4010,26 @@ addition to creating a symbol version (as if
|
||||
@code{"@var{name2}@@@var{nodename}"} was used) the version will be also used
|
||||
to resolve @var{name2} by the linker.
|
||||
|
||||
@item tainted_args
|
||||
@cindex @code{tainted_args} function attribute
|
||||
The @code{tainted_args} attribute is used to specify that a function is called
|
||||
in a way that requires sanitization of its arguments, such as a system
|
||||
call in an operating system kernel. Such a function can be considered part
|
||||
of the ``attack surface'' of the program. The attribute can be used both
|
||||
on function declarations, and on field declarations containing function
|
||||
pointers. In the latter case, any function used as an initializer of
|
||||
such a callback field will be treated as being called with tainted
|
||||
arguments.
|
||||
|
||||
The analyzer will pay particular attention to such functions when both
|
||||
@option{-fanalyzer} and @option{-fanalyzer-checker=taint} are supplied,
|
||||
potentially issuing warnings guarded by
|
||||
@option{-Wanalyzer-tainted-allocation-size},
|
||||
@option{-Wanalyzer-tainted-array-index},
|
||||
@option{-Wanalyzer-tainted-divisor},
|
||||
@option{-Wanalyzer-tainted-offset},
|
||||
and @option{-Wanalyzer-tainted-size}.
|
||||
|
||||
@item target_clones (@var{options})
|
||||
@cindex @code{target_clones} function attribute
|
||||
The @code{target_clones} attribute is used to specify that a function
|
||||
|
||||
88
gcc/testsuite/gcc.dg/analyzer/attr-tainted_args-1.c
Normal file
88
gcc/testsuite/gcc.dg/analyzer/attr-tainted_args-1.c
Normal file
@ -0,0 +1,88 @@
|
||||
// TODO: remove need for this option
|
||||
/* { dg-additional-options "-fanalyzer-checker=taint" } */
|
||||
|
||||
#include "analyzer-decls.h"
|
||||
|
||||
struct arg_buf
|
||||
{
|
||||
int i;
|
||||
int j;
|
||||
};
|
||||
|
||||
/* Example of marking a function as tainted. */
|
||||
|
||||
void __attribute__((tainted_args))
|
||||
test_1 (int i, void *p, char *q)
|
||||
{
|
||||
/* There should be a single enode,
|
||||
for the "tainted" entry to the function. */
|
||||
__analyzer_dump_exploded_nodes (0); /* { dg-warning "1 processed enode" } */
|
||||
|
||||
__analyzer_dump_state ("taint", i); /* { dg-warning "state: 'tainted'" } */
|
||||
__analyzer_dump_state ("taint", p); /* { dg-warning "state: 'tainted'" } */
|
||||
__analyzer_dump_state ("taint", q); /* { dg-warning "state: 'tainted'" } */
|
||||
__analyzer_dump_state ("taint", *q); /* { dg-warning "state: 'tainted'" } */
|
||||
|
||||
struct arg_buf *args = p;
|
||||
__analyzer_dump_state ("taint", args->i); /* { dg-warning "state: 'tainted'" } */
|
||||
__analyzer_dump_state ("taint", args->j); /* { dg-warning "state: 'tainted'" } */
|
||||
}
|
||||
|
||||
/* Example of marking a callback field as tainted. */
|
||||
|
||||
struct s2
|
||||
{
|
||||
void (*cb) (int, void *, char *)
|
||||
__attribute__((tainted_args));
|
||||
};
|
||||
|
||||
/* Function not marked as tainted. */
|
||||
|
||||
void
|
||||
test_2a (int i, void *p, char *q)
|
||||
{
|
||||
/* There should be a single enode,
|
||||
for the normal entry to the function. */
|
||||
__analyzer_dump_exploded_nodes (0); /* { dg-warning "1 processed enode" } */
|
||||
|
||||
__analyzer_dump_state ("taint", i); /* { dg-warning "state: 'start'" } */
|
||||
__analyzer_dump_state ("taint", p); /* { dg-warning "state: 'start'" } */
|
||||
__analyzer_dump_state ("taint", q); /* { dg-warning "state: 'start'" } */
|
||||
|
||||
struct arg_buf *args = p;
|
||||
__analyzer_dump_state ("taint", args->i); /* { dg-warning "state: 'start'" } */
|
||||
__analyzer_dump_state ("taint", args->j); /* { dg-warning "state: 'start'" } */
|
||||
}
|
||||
|
||||
/* Function referenced via t2b.cb, marked as "tainted". */
|
||||
|
||||
void
|
||||
test_2b (int i, void *p, char *q)
|
||||
{
|
||||
/* There should be two enodes
|
||||
for the direct call, and the "tainted" entry to the function. */
|
||||
__analyzer_dump_exploded_nodes (0); /* { dg-warning "2 processed enodes" } */
|
||||
}
|
||||
|
||||
/* Callback used via t2c.cb, marked as "tainted". */
|
||||
void
|
||||
__analyzer_test_2c (int i, void *p, char *q)
|
||||
{
|
||||
/* There should be a single enode,
|
||||
for the "tainted" entry to the function. */
|
||||
__analyzer_dump_exploded_nodes (0); /* { dg-warning "1 processed enode" } */
|
||||
|
||||
__analyzer_dump_state ("taint", i); /* { dg-warning "state: 'tainted'" } */
|
||||
__analyzer_dump_state ("taint", p); /* { dg-warning "state: 'tainted'" } */
|
||||
__analyzer_dump_state ("taint", q); /* { dg-warning "state: 'tainted'" } */
|
||||
}
|
||||
|
||||
struct s2 t2b =
|
||||
{
|
||||
.cb = test_2b
|
||||
};
|
||||
|
||||
struct s2 t2c =
|
||||
{
|
||||
.cb = __analyzer_test_2c
|
||||
};
|
||||
@ -0,0 +1,6 @@
|
||||
int not_a_fn __attribute__ ((tainted_args)); /* { dg-warning "'tainted_args' attribute ignored; valid only for functions and function pointer fields" } */
|
||||
|
||||
struct s
|
||||
{
|
||||
int f __attribute__ ((tainted_args)); /* { dg-warning "'tainted_args' attribute ignored; field must be a function pointer" } */
|
||||
};
|
||||
93
gcc/testsuite/gcc.dg/analyzer/taint-CVE-2011-2210-1.c
Normal file
93
gcc/testsuite/gcc.dg/analyzer/taint-CVE-2011-2210-1.c
Normal file
@ -0,0 +1,93 @@
|
||||
/* "The osf_getsysinfo function in arch/alpha/kernel/osf_sys.c in the
|
||||
Linux kernel before 2.6.39.4 on the Alpha platform does not properly
|
||||
restrict the data size for GSI_GET_HWRPB operations, which allows
|
||||
local users to obtain sensitive information from kernel memory via
|
||||
a crafted call."
|
||||
|
||||
Fixed in 3d0475119d8722798db5e88f26493f6547a4bb5b on linux-2.6.39.y
|
||||
in linux-stable. */
|
||||
|
||||
// TODO: remove need for this option:
|
||||
/* { dg-additional-options "-fanalyzer-checker=taint" } */
|
||||
|
||||
#include "analyzer-decls.h"
|
||||
#include "test-uaccess.h"
|
||||
|
||||
/* Adapted from include/linux/linkage.h. */
|
||||
|
||||
#define asmlinkage
|
||||
|
||||
/* Adapted from include/linux/syscalls.h. */
|
||||
|
||||
#define __SC_DECL1(t1, a1) t1 a1
|
||||
#define __SC_DECL2(t2, a2, ...) t2 a2, __SC_DECL1(__VA_ARGS__)
|
||||
#define __SC_DECL3(t3, a3, ...) t3 a3, __SC_DECL2(__VA_ARGS__)
|
||||
#define __SC_DECL4(t4, a4, ...) t4 a4, __SC_DECL3(__VA_ARGS__)
|
||||
#define __SC_DECL5(t5, a5, ...) t5 a5, __SC_DECL4(__VA_ARGS__)
|
||||
#define __SC_DECL6(t6, a6, ...) t6 a6, __SC_DECL5(__VA_ARGS__)
|
||||
|
||||
#define SYSCALL_DEFINEx(x, sname, ...) \
|
||||
__SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
|
||||
|
||||
#define SYSCALL_DEFINE(name) asmlinkage long sys_##name
|
||||
#define __SYSCALL_DEFINEx(x, name, ...) \
|
||||
asmlinkage __attribute__((tainted_args)) \
|
||||
long sys##name(__SC_DECL##x(__VA_ARGS__))
|
||||
|
||||
#define SYSCALL_DEFINE5(name, ...) SYSCALL_DEFINEx(5, _##name, __VA_ARGS__)
|
||||
|
||||
/* Adapted from arch/alpha/include/asm/hwrpb.h. */
|
||||
|
||||
struct hwrpb_struct {
|
||||
unsigned long phys_addr; /* check: physical address of the hwrpb */
|
||||
unsigned long id; /* check: "HWRPB\0\0\0" */
|
||||
unsigned long revision;
|
||||
unsigned long size; /* size of hwrpb */
|
||||
/* [...snip...] */
|
||||
};
|
||||
|
||||
extern struct hwrpb_struct *hwrpb;
|
||||
|
||||
/* Adapted from arch/alpha/kernel/osf_sys.c. */
|
||||
|
||||
SYSCALL_DEFINE5(osf_getsysinfo, unsigned long, op, void __user *, buffer,
|
||||
unsigned long, nbytes, int __user *, start, void __user *, arg)
|
||||
{
|
||||
/* [...snip...] */
|
||||
|
||||
__analyzer_dump_state ("taint", nbytes); /* { dg-warning "tainted" } */
|
||||
|
||||
/* TODO: should have an event explaining why "nbytes" is treated as
|
||||
attacker-controlled. */
|
||||
|
||||
/* case GSI_GET_HWRPB: */
|
||||
if (nbytes < sizeof(*hwrpb))
|
||||
return -1;
|
||||
|
||||
__analyzer_dump_state ("taint", nbytes); /* { dg-warning "has_lb" } */
|
||||
|
||||
if (copy_to_user(buffer, hwrpb, nbytes) != 0) /* { dg-warning "use of attacker-controlled value 'nbytes' as size without upper-bounds checking" } */
|
||||
return -2;
|
||||
|
||||
return 1;
|
||||
|
||||
/* [...snip...] */
|
||||
}
|
||||
|
||||
/* With the fix for the sense of the size comparison. */
|
||||
|
||||
SYSCALL_DEFINE5(osf_getsysinfo_fixed, unsigned long, op, void __user *, buffer,
|
||||
unsigned long, nbytes, int __user *, start, void __user *, arg)
|
||||
{
|
||||
/* [...snip...] */
|
||||
|
||||
/* case GSI_GET_HWRPB: */
|
||||
if (nbytes > sizeof(*hwrpb))
|
||||
return -1;
|
||||
if (copy_to_user(buffer, hwrpb, nbytes) != 0) /* { dg-bogus "attacker-controlled" } */
|
||||
return -2;
|
||||
|
||||
return 1;
|
||||
|
||||
/* [...snip...] */
|
||||
}
|
||||
38
gcc/testsuite/gcc.dg/analyzer/taint-CVE-2020-13143-1.c
Normal file
38
gcc/testsuite/gcc.dg/analyzer/taint-CVE-2020-13143-1.c
Normal file
@ -0,0 +1,38 @@
|
||||
/* See notes in this header. */
|
||||
#include "taint-CVE-2020-13143.h"
|
||||
|
||||
// TODO: remove need for this option
|
||||
/* { dg-additional-options "-fanalyzer-checker=taint" } */
|
||||
|
||||
struct configfs_attribute {
|
||||
/* [...snip...] */
|
||||
ssize_t (*store)(struct config_item *, const char *, size_t) /* { dg-message "\\(1\\) field 'store' of 'struct configfs_attribute' is marked with '__attribute__\\(\\(tainted_args\\)\\)'" } */
|
||||
__attribute__((tainted_args)); /* (this is added). */
|
||||
};
|
||||
static inline struct gadget_info *to_gadget_info(struct config_item *item)
|
||||
{
|
||||
return container_of(to_config_group(item), struct gadget_info, group);
|
||||
}
|
||||
|
||||
static ssize_t gadget_dev_desc_UDC_store(struct config_item *item,
|
||||
const char *page, size_t len)
|
||||
{
|
||||
struct gadget_info *gi = to_gadget_info(item);
|
||||
char *name;
|
||||
int ret;
|
||||
|
||||
#if 0
|
||||
/* FIXME: this is the fix. */
|
||||
if (strlen(page) < len)
|
||||
return -EOVERFLOW;
|
||||
#endif
|
||||
|
||||
name = kstrdup(page, GFP_KERNEL);
|
||||
if (!name)
|
||||
return -ENOMEM;
|
||||
if (name[len - 1] == '\n') /* { dg-warning "use of attacker-controlled value 'len \[^\n\r\]+' as offset without upper-bounds checking" } */
|
||||
name[len - 1] = '\0'; /* { dg-warning "use of attacker-controlled value 'len \[^\n\r\]+' as offset without upper-bounds checking" } */
|
||||
/* [...snip...] */ \
|
||||
}
|
||||
|
||||
CONFIGFS_ATTR(gadget_dev_desc_, UDC); /* { dg-message "\\(2\\) function 'gadget_dev_desc_UDC_store' used as initializer for field 'store' marked with '__attribute__\\(\\(tainted_args\\)\\)'" } */
|
||||
32
gcc/testsuite/gcc.dg/analyzer/taint-CVE-2020-13143-2.c
Normal file
32
gcc/testsuite/gcc.dg/analyzer/taint-CVE-2020-13143-2.c
Normal file
@ -0,0 +1,32 @@
|
||||
/* See notes in this header. */
|
||||
#include "taint-CVE-2020-13143.h"
|
||||
|
||||
// TODO: remove need for this option
|
||||
/* { dg-additional-options "-fanalyzer-checker=taint" } */
|
||||
|
||||
struct configfs_attribute {
|
||||
/* [...snip...] */
|
||||
ssize_t (*store)(struct config_item *, const char *, size_t) /* { dg-message "\\(1\\) field 'store' of 'struct configfs_attribute' is marked with '__attribute__\\(\\(tainted_args\\)\\)'" } */
|
||||
__attribute__((tainted_args)); /* (this is added). */
|
||||
};
|
||||
|
||||
/* Highly simplified version. */
|
||||
|
||||
static ssize_t gadget_dev_desc_UDC_store(struct config_item *item,
|
||||
const char *page, size_t len)
|
||||
{
|
||||
/* TODO: ought to have state_change_event talking about where the tainted value comes from. */
|
||||
|
||||
char *name;
|
||||
/* [...snip...] */
|
||||
|
||||
name = kstrdup(page, GFP_KERNEL);
|
||||
if (!name)
|
||||
return -ENOMEM;
|
||||
if (name[len - 1] == '\n') /* { dg-warning "use of attacker-controlled value 'len \[^\n\r\]+' as offset without upper-bounds checking" } */
|
||||
name[len - 1] = '\0'; /* { dg-warning "use of attacker-controlled value 'len \[^\n\r\]+' as offset without upper-bounds checking" } */
|
||||
/* [...snip...] */
|
||||
return 0;
|
||||
}
|
||||
|
||||
CONFIGFS_ATTR(gadget_dev_desc_, UDC); /* { dg-message "\\(2\\) function 'gadget_dev_desc_UDC_store' used as initializer for field 'store' marked with '__attribute__\\(\\(tainted_args\\)\\)'" } */
|
||||
91
gcc/testsuite/gcc.dg/analyzer/taint-CVE-2020-13143.h
Normal file
91
gcc/testsuite/gcc.dg/analyzer/taint-CVE-2020-13143.h
Normal file
@ -0,0 +1,91 @@
|
||||
/* Shared header for the various taint-CVE-2020-13143.h tests.
|
||||
|
||||
"gadget_dev_desc_UDC_store in drivers/usb/gadget/configfs.c in the
|
||||
Linux kernel 3.16 through 5.6.13 relies on kstrdup without considering
|
||||
the possibility of an internal '\0' value, which allows attackers to
|
||||
trigger an out-of-bounds read, aka CID-15753588bcd4."
|
||||
|
||||
Fixed by 15753588bcd4bbffae1cca33c8ced5722477fe1f on linux-5.7.y
|
||||
in linux-stable. */
|
||||
|
||||
// TODO: remove need for this option
|
||||
/* { dg-additional-options "-fanalyzer-checker=taint" } */
|
||||
|
||||
#include <stddef.h>
|
||||
|
||||
/* Adapted from include/uapi/asm-generic/posix_types.h */
|
||||
|
||||
typedef unsigned int __kernel_size_t;
|
||||
typedef int __kernel_ssize_t;
|
||||
|
||||
/* Adapted from include/linux/types.h */
|
||||
|
||||
//typedef __kernel_size_t size_t;
|
||||
typedef __kernel_ssize_t ssize_t;
|
||||
|
||||
/* Adapted from include/linux/kernel.h */
|
||||
|
||||
#define container_of(ptr, type, member) ({ \
|
||||
void *__mptr = (void *)(ptr); \
|
||||
/* [...snip...] */ \
|
||||
((type *)(__mptr - offsetof(type, member))); })
|
||||
|
||||
/* Adapted from include/linux/configfs.h */
|
||||
|
||||
struct config_item {
|
||||
/* [...snip...] */
|
||||
};
|
||||
|
||||
struct config_group {
|
||||
struct config_item cg_item;
|
||||
/* [...snip...] */
|
||||
};
|
||||
|
||||
static inline struct config_group *to_config_group(struct config_item *item)
|
||||
{
|
||||
return item ? container_of(item,struct config_group,cg_item) : NULL;
|
||||
}
|
||||
|
||||
#define CONFIGFS_ATTR(_pfx, _name) \
|
||||
static struct configfs_attribute _pfx##attr_##_name = { \
|
||||
/* [...snip...] */ \
|
||||
.store = _pfx##_name##_store, \
|
||||
}
|
||||
|
||||
/* Adapted from include/linux/compiler.h */
|
||||
|
||||
#define __force
|
||||
|
||||
/* Adapted from include/asm-generic/errno-base.h */
|
||||
|
||||
#define ENOMEM 12 /* Out of memory */
|
||||
|
||||
/* Adapted from include/linux/types.h */
|
||||
|
||||
#define __bitwise__
|
||||
typedef unsigned __bitwise__ gfp_t;
|
||||
|
||||
/* Adapted from include/linux/gfp.h */
|
||||
|
||||
#define ___GFP_WAIT 0x10u
|
||||
#define ___GFP_IO 0x40u
|
||||
#define ___GFP_FS 0x80u
|
||||
#define __GFP_WAIT ((__force gfp_t)___GFP_WAIT)
|
||||
#define __GFP_IO ((__force gfp_t)___GFP_IO)
|
||||
#define __GFP_FS ((__force gfp_t)___GFP_FS)
|
||||
#define GFP_KERNEL (__GFP_WAIT | __GFP_IO | __GFP_FS)
|
||||
|
||||
/* Adapted from include/linux/compiler_attributes.h */
|
||||
|
||||
#define __malloc __attribute__((__malloc__))
|
||||
|
||||
/* Adapted from include/linux/string.h */
|
||||
|
||||
extern char *kstrdup(const char *s, gfp_t gfp) __malloc;
|
||||
|
||||
/* Adapted from drivers/usb/gadget/configfs.c */
|
||||
|
||||
struct gadget_info {
|
||||
struct config_group group;
|
||||
/* [...snip...] */ \
|
||||
};
|
||||
21
gcc/testsuite/gcc.dg/analyzer/taint-alloc-3.c
Normal file
21
gcc/testsuite/gcc.dg/analyzer/taint-alloc-3.c
Normal file
@ -0,0 +1,21 @@
|
||||
// TODO: remove need for this option:
|
||||
/* { dg-additional-options "-fanalyzer-checker=taint" } */
|
||||
|
||||
#include "analyzer-decls.h"
|
||||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
#include <string.h>
|
||||
|
||||
/* malloc with tainted size from a syscall. */
|
||||
|
||||
void *p;
|
||||
|
||||
void __attribute__((tainted_args))
|
||||
test_1 (size_t sz) /* { dg-message "\\(1\\) function 'test_1' marked with '__attribute__\\(\\(tainted_args\\)\\)'" } */
|
||||
{
|
||||
/* TODO: should have a message saying why "sz" is tainted, e.g.
|
||||
"treating 'sz' as attacker-controlled because 'test_1' is marked with '__attribute__((tainted_args))'" */
|
||||
|
||||
p = malloc (sz); /* { dg-warning "use of attacker-controlled value 'sz' as allocation size without upper-bounds checking" "warning" } */
|
||||
/* { dg-message "\\(\[0-9\]+\\) use of attacker-controlled value 'sz' as allocation size without upper-bounds checking" "final event" { target *-*-* } .-1 } */
|
||||
}
|
||||
31
gcc/testsuite/gcc.dg/analyzer/taint-alloc-4.c
Normal file
31
gcc/testsuite/gcc.dg/analyzer/taint-alloc-4.c
Normal file
@ -0,0 +1,31 @@
|
||||
// TODO: remove need for this option:
|
||||
/* { dg-additional-options "-fanalyzer-checker=taint" } */
|
||||
|
||||
#include "analyzer-decls.h"
|
||||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
#include <string.h>
|
||||
|
||||
/* malloc with tainted size from a syscall. */
|
||||
|
||||
struct arg_buf
|
||||
{
|
||||
size_t sz;
|
||||
};
|
||||
|
||||
void *p;
|
||||
|
||||
void __attribute__((tainted_args))
|
||||
test_1 (void *data) /* { dg-message "\\(1\\) function 'test_1' marked with '__attribute__\\(\\(tainted_args\\)\\)'" } */
|
||||
{
|
||||
/* we should treat pointed-to-structs as tainted. */
|
||||
__analyzer_dump_state ("taint", data); /* { dg-warning "state: 'tainted'" } */
|
||||
|
||||
struct arg_buf *args = data;
|
||||
|
||||
__analyzer_dump_state ("taint", args); /* { dg-warning "state: 'tainted'" } */
|
||||
__analyzer_dump_state ("taint", args->sz); /* { dg-warning "state: 'tainted'" } */
|
||||
|
||||
p = malloc (args->sz); /* { dg-warning "use of attacker-controlled value '\\*args.sz' as allocation size without upper-bounds checking" "warning" } */
|
||||
/* { dg-message "\\(\[0-9\]+\\) use of attacker-controlled value '\\*args.sz' as allocation size without upper-bounds checking" "final event" { target *-*-* } .-1 } */
|
||||
}
|
||||
15
gcc/testsuite/gcc.dg/analyzer/test-uaccess.h
Normal file
15
gcc/testsuite/gcc.dg/analyzer/test-uaccess.h
Normal file
@ -0,0 +1,15 @@
|
||||
/* Shared header for testcases for copy_from_user/copy_to_user. */
|
||||
|
||||
/* Adapted from include/linux/compiler.h */
|
||||
|
||||
#define __user
|
||||
|
||||
/* Adapted from include/asm-generic/uaccess.h */
|
||||
|
||||
extern int copy_from_user(void *to, const void __user *from, long n)
|
||||
__attribute__((access (write_only, 1, 3),
|
||||
access (read_only, 2, 3)));
|
||||
|
||||
extern long copy_to_user(void __user *to, const void *from, unsigned long n)
|
||||
__attribute__((access (write_only, 1, 3),
|
||||
access (read_only, 2, 3)));
|
||||
Loading…
Reference in New Issue
Block a user