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dwarf.c (read_uleb128): Fix overflow test.

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* dwarf.c (read_uleb128): Fix overflow test.
	(read_sleb128): Likewise.
	(build_address_map): Don't change unit_buf.start.

From-SVN: r192053
This commit is contained in:
Ian Lance Taylor 2012-10-03 22:07:12 +00:00 committed by Ian Lance Taylor
parent 91ba65f2f0
commit be4ba8aef3
2 changed files with 25 additions and 10 deletions
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6
libbacktrace/ChangeLog
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@ -1,3 +1,9 @@
2012-10-03 Ian Lance Taylor <iant@google.com>
* dwarf.c (read_uleb128): Fix overflow test.
(read_sleb128): Likewise.
(build_address_map): Don't change unit_buf.start.
2012-10-02 Uros Bizjak <ubizjak@gmail.com> 2012-10-02 Uros Bizjak <ubizjak@gmail.com>
PR other/54761 PR other/54761

29
libbacktrace/dwarf.c
View File

@ -524,10 +524,12 @@ read_uleb128 (struct dwarf_buf *buf)
{ {
uint64_t ret; uint64_t ret;
unsigned int shift; unsigned int shift;
int overflow;
unsigned char b; unsigned char b;
ret = 0; ret = 0;
shift = 0; shift = 0;
overflow = 0;
do do
{ {
const unsigned char *p; const unsigned char *p;
@ -536,14 +538,17 @@ read_uleb128 (struct dwarf_buf *buf)
if (!advance (buf, 1)) if (!advance (buf, 1))
return 0; return 0;
b = *p; b = *p;
ret |= ((uint64_t) (b & 0x7f)) << shift; if (shift < 64)
ret |= ((uint64_t) (b & 0x7f)) << shift;
else if (!overflow)
{
dwarf_buf_error (buf, "LEB128 overflows uint64_t");
overflow = 1;
}
shift += 7; shift += 7;
} }
while ((b & 0x80) != 0); while ((b & 0x80) != 0);
if (shift > 64)
dwarf_buf_error (buf, "LEB128 overflows uint64_5");
return ret; return ret;
} }
@ -554,10 +559,12 @@ read_sleb128 (struct dwarf_buf *buf)
{ {
uint64_t val; uint64_t val;
unsigned int shift; unsigned int shift;
int overflow;
unsigned char b; unsigned char b;
val = 0; val = 0;
shift = 0; shift = 0;
overflow = 0;
do do
{ {
const unsigned char *p; const unsigned char *p;
@ -566,15 +573,18 @@ read_sleb128 (struct dwarf_buf *buf)
if (!advance (buf, 1)) if (!advance (buf, 1))
return 0; return 0;
b = *p; b = *p;
val |= ((uint64_t) (b & 0x7f)) << shift; if (shift < 64)
val |= ((uint64_t) (b & 0x7f)) << shift;
else if (!overflow)
{
dwarf_buf_error (buf, "signed LEB128 overflows uint64_t");
overflow = 1;
}
shift += 7; shift += 7;
} }
while ((b & 0x80) != 0); while ((b & 0x80) != 0);
if (shift > 64) if ((b & 0x40) != 0 && shift < 64)
dwarf_buf_error (buf, "signed LEB128 overflows uint64_t");
if ((b & 0x40) != 0)
val |= ((uint64_t) -1) << shift; val |= ((uint64_t) -1) << shift;
return (int64_t) val; return (int64_t) val;
@ -1262,7 +1272,6 @@ build_address_map (struct backtrace_state *state,
} }
unit_buf = info; unit_buf = info;
unit_buf.start = info.buf;
unit_buf.left = len; unit_buf.left = len;
if (!advance (&info, len)) if (!advance (&info, len))