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linux-user: Fix types in uaccess.c 

For copy_*_user, only 0 and -TARGET_EFAULT are returned; no need
to involve abi_long.  Use size_t for lengths.  Use bool for the
lock_user copy argument.  Use ssize_t for target_strlen, because
we can't overflow the host memory space.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20210212184902.1251044-19-richard.henderson@linaro.org
[PMM: moved fix for ifdef error to previous commit]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Richard Henderson 2021-02-12 10:48:49 -08:00 committed by Peter Maydell
parent 687ca79789
commit 09f679b62d
2 changed files with 28 additions and 29 deletions
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12
linux-user/qemu.h
View File

@ -7,8 +7,6 @@
#include "exec/cpu_ldst.h" #include "exec/cpu_ldst.h"
#undef DEBUG_REMAP #undef DEBUG_REMAP
#ifdef DEBUG_REMAP
#endif /* DEBUG_REMAP */
#include "exec/user/abitypes.h" #include "exec/user/abitypes.h"
@ -629,8 +627,8 @@ static inline bool access_ok(CPUState *cpu, int type,
* buffers between the target and host. These internally perform * buffers between the target and host. These internally perform
* locking/unlocking of the memory. * locking/unlocking of the memory.
*/ */
abi_long copy_from_user(void *hptr, abi_ulong gaddr, size_t len); int copy_from_user(void *hptr, abi_ulong gaddr, size_t len);
abi_long copy_to_user(abi_ulong gaddr, void *hptr, size_t len); int copy_to_user(abi_ulong gaddr, void *hptr, size_t len);
/* Functions for accessing guest memory. The tget and tput functions /* Functions for accessing guest memory. The tget and tput functions
read/write single values, byteswapping as necessary. The lock_user function read/write single values, byteswapping as necessary. The lock_user function
@ -640,13 +638,13 @@ abi_long copy_to_user(abi_ulong gaddr, void *hptr, size_t len);
/* Lock an area of guest memory into the host. If copy is true then the /* Lock an area of guest memory into the host. If copy is true then the
host area will have the same contents as the guest. */ host area will have the same contents as the guest. */
void *lock_user(int type, abi_ulong guest_addr, long len, int copy); void *lock_user(int type, abi_ulong guest_addr, size_t len, bool copy);
/* Unlock an area of guest memory. The first LEN bytes must be /* Unlock an area of guest memory. The first LEN bytes must be
flushed back to guest memory. host_ptr = NULL is explicitly flushed back to guest memory. host_ptr = NULL is explicitly
allowed and does nothing. */ allowed and does nothing. */
#ifndef DEBUG_REMAP #ifndef DEBUG_REMAP
static inline void unlock_user(void *host_ptr, abi_ulong guest_addr, long len) static inline void unlock_user(void *host_ptr, abi_ulong guest_addr, size_t len)
{ } { }
#else #else
void unlock_user(void *host_ptr, abi_ulong guest_addr, long len); void unlock_user(void *host_ptr, abi_ulong guest_addr, long len);
@ -654,7 +652,7 @@ void unlock_user(void *host_ptr, abi_ulong guest_addr, long len);
/* Return the length of a string in target memory or -TARGET_EFAULT if /* Return the length of a string in target memory or -TARGET_EFAULT if
access error. */ access error. */
abi_long target_strlen(abi_ulong gaddr); ssize_t target_strlen(abi_ulong gaddr);
/* Like lock_user but for null terminated strings. */ /* Like lock_user but for null terminated strings. */
void *lock_user_string(abi_ulong guest_addr); void *lock_user_string(abi_ulong guest_addr);

45
linux-user/uaccess.c
View File

@ -4,7 +4,7 @@
#include "qemu.h" #include "qemu.h"
void *lock_user(int type, abi_ulong guest_addr, long len, int copy) void *lock_user(int type, abi_ulong guest_addr, size_t len, bool copy)
{ {
if (!access_ok_untagged(type, guest_addr, len)) { if (!access_ok_untagged(type, guest_addr, len)) {
return NULL; return NULL;
@ -26,7 +26,7 @@ void *lock_user(int type, abi_ulong guest_addr, long len, int copy)
} }
#ifdef DEBUG_REMAP #ifdef DEBUG_REMAP
void unlock_user(void *host_ptr, abi_ulong guest_addr, long len); void unlock_user(void *host_ptr, abi_ulong guest_addr, size_t len);
{ {
if (!host_ptr) { if (!host_ptr) {
return; return;
@ -34,7 +34,7 @@ void unlock_user(void *host_ptr, abi_ulong guest_addr, long len);
if (host_ptr == g2h_untagged(guest_addr)) { if (host_ptr == g2h_untagged(guest_addr)) {
return; return;
} }
if (len > 0) { if (len != 0) {
memcpy(g2h_untagged(guest_addr), host_ptr, len); memcpy(g2h_untagged(guest_addr), host_ptr, len);
} }
g_free(host_ptr); g_free(host_ptr);
@ -43,53 +43,53 @@ void unlock_user(void *host_ptr, abi_ulong guest_addr, long len);
void *lock_user_string(abi_ulong guest_addr) void *lock_user_string(abi_ulong guest_addr)
{ {
abi_long len = target_strlen(guest_addr); ssize_t len = target_strlen(guest_addr);
if (len < 0) { if (len < 0) {
return NULL; return NULL;
} }
return lock_user(VERIFY_READ, guest_addr, (long)(len + 1), 1); return lock_user(VERIFY_READ, guest_addr, (size_t)len + 1, 1);
} }
/* copy_from_user() and copy_to_user() are usually used to copy data /* copy_from_user() and copy_to_user() are usually used to copy data
* buffers between the target and host. These internally perform * buffers between the target and host. These internally perform
* locking/unlocking of the memory. * locking/unlocking of the memory.
*/ */
abi_long copy_from_user(void *hptr, abi_ulong gaddr, size_t len) int copy_from_user(void *hptr, abi_ulong gaddr, size_t len)
{ {
abi_long ret = 0; int ret = 0;
void *ghptr; void *ghptr = lock_user(VERIFY_READ, gaddr, len, 1);
if ((ghptr = lock_user(VERIFY_READ, gaddr, len, 1))) { if (ghptr) {
memcpy(hptr, ghptr, len); memcpy(hptr, ghptr, len);
unlock_user(ghptr, gaddr, 0); unlock_user(ghptr, gaddr, 0);
} else } else {
ret = -TARGET_EFAULT; ret = -TARGET_EFAULT;
}
return ret; return ret;
} }
int copy_to_user(abi_ulong gaddr, void *hptr, size_t len)
abi_long copy_to_user(abi_ulong gaddr, void *hptr, size_t len)
{ {
abi_long ret = 0; int ret = 0;
void *ghptr; void *ghptr = lock_user(VERIFY_WRITE, gaddr, len, 0);
if ((ghptr = lock_user(VERIFY_WRITE, gaddr, len, 0))) { if (ghptr) {
memcpy(ghptr, hptr, len); memcpy(ghptr, hptr, len);
unlock_user(ghptr, gaddr, len); unlock_user(ghptr, gaddr, len);
} else } else {
ret = -TARGET_EFAULT; ret = -TARGET_EFAULT;
}
return ret; return ret;
} }
/* Return the length of a string in target memory or -TARGET_EFAULT if /* Return the length of a string in target memory or -TARGET_EFAULT if
access error */ access error */
abi_long target_strlen(abi_ulong guest_addr1) ssize_t target_strlen(abi_ulong guest_addr1)
{ {
uint8_t *ptr; uint8_t *ptr;
abi_ulong guest_addr; abi_ulong guest_addr;
int max_len, len; size_t max_len, len;
guest_addr = guest_addr1; guest_addr = guest_addr1;
for(;;) { for(;;) {
@ -101,11 +101,12 @@ abi_long target_strlen(abi_ulong guest_addr1)
unlock_user(ptr, guest_addr, 0); unlock_user(ptr, guest_addr, 0);
guest_addr += len; guest_addr += len;
/* we don't allow wrapping or integer overflow */ /* we don't allow wrapping or integer overflow */
if (guest_addr == 0 || if (guest_addr == 0 || (guest_addr - guest_addr1) > 0x7fffffff) {
(guest_addr - guest_addr1) > 0x7fffffff)
return -TARGET_EFAULT; return -TARGET_EFAULT;
if (len != max_len) }
if (len != max_len) {
break; break;
}
} }
return guest_addr - guest_addr1; return guest_addr - guest_addr1;
} }