Commit 753c05dc authored by James Hogan's avatar James Hogan Committed by Greg Kroah-Hartman

metag/usercopy: Add early abort to copy_to_user

commit fb8ea062 upstream.

When copying to userland on Meta, if any faults are encountered
immediately abort the copy instead of continuing on and repeatedly
faulting, and worse potentially copying further bytes successfully to
subsequent valid pages.

Fixes: 373cd784 ("metag: Memory handling")
Reported-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarJames Hogan <james.hogan@imgtec.com>
Cc: linux-metag@vger.kernel.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 63916ca6
...@@ -538,23 +538,31 @@ unsigned long __copy_user(void __user *pdst, const void *psrc, ...@@ -538,23 +538,31 @@ unsigned long __copy_user(void __user *pdst, const void *psrc,
if ((unsigned long) src & 1) { if ((unsigned long) src & 1) {
__asm_copy_to_user_1(dst, src, retn); __asm_copy_to_user_1(dst, src, retn);
n--; n--;
if (retn)
return retn + n;
} }
if ((unsigned long) dst & 1) { if ((unsigned long) dst & 1) {
/* Worst case - byte copy */ /* Worst case - byte copy */
while (n > 0) { while (n > 0) {
__asm_copy_to_user_1(dst, src, retn); __asm_copy_to_user_1(dst, src, retn);
n--; n--;
if (retn)
return retn + n;
} }
} }
if (((unsigned long) src & 2) && n >= 2) { if (((unsigned long) src & 2) && n >= 2) {
__asm_copy_to_user_2(dst, src, retn); __asm_copy_to_user_2(dst, src, retn);
n -= 2; n -= 2;
if (retn)
return retn + n;
} }
if ((unsigned long) dst & 2) { if ((unsigned long) dst & 2) {
/* Second worst case - word copy */ /* Second worst case - word copy */
while (n >= 2) { while (n >= 2) {
__asm_copy_to_user_2(dst, src, retn); __asm_copy_to_user_2(dst, src, retn);
n -= 2; n -= 2;
if (retn)
return retn + n;
} }
} }
...@@ -569,6 +577,8 @@ unsigned long __copy_user(void __user *pdst, const void *psrc, ...@@ -569,6 +577,8 @@ unsigned long __copy_user(void __user *pdst, const void *psrc,
while (n >= 8) { while (n >= 8) {
__asm_copy_to_user_8x64(dst, src, retn); __asm_copy_to_user_8x64(dst, src, retn);
n -= 8; n -= 8;
if (retn)
return retn + n;
} }
} }
if (n >= RAPF_MIN_BUF_SIZE) { if (n >= RAPF_MIN_BUF_SIZE) {
...@@ -581,6 +591,8 @@ unsigned long __copy_user(void __user *pdst, const void *psrc, ...@@ -581,6 +591,8 @@ unsigned long __copy_user(void __user *pdst, const void *psrc,
while (n >= 8) { while (n >= 8) {
__asm_copy_to_user_8x64(dst, src, retn); __asm_copy_to_user_8x64(dst, src, retn);
n -= 8; n -= 8;
if (retn)
return retn + n;
} }
} }
#endif #endif
...@@ -588,11 +600,15 @@ unsigned long __copy_user(void __user *pdst, const void *psrc, ...@@ -588,11 +600,15 @@ unsigned long __copy_user(void __user *pdst, const void *psrc,
while (n >= 16) { while (n >= 16) {
__asm_copy_to_user_16(dst, src, retn); __asm_copy_to_user_16(dst, src, retn);
n -= 16; n -= 16;
if (retn)
return retn + n;
} }
while (n >= 4) { while (n >= 4) {
__asm_copy_to_user_4(dst, src, retn); __asm_copy_to_user_4(dst, src, retn);
n -= 4; n -= 4;
if (retn)
return retn + n;
} }
switch (n) { switch (n) {
...@@ -609,6 +625,10 @@ unsigned long __copy_user(void __user *pdst, const void *psrc, ...@@ -609,6 +625,10 @@ unsigned long __copy_user(void __user *pdst, const void *psrc,
break; break;
} }
/*
* If we get here, retn correctly reflects the number of failing
* bytes.
*/
return retn; return retn;
} }
EXPORT_SYMBOL(__copy_user); EXPORT_SYMBOL(__copy_user);
......
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