[PATCH v3] arm: memcpy: fix copying big data does not meet expectations [BZ #25620]
zhuyan (M)
zhuyan34@huawei.com
Tue May 12 12:01:53 GMT 2020
In ARMv7, the memcpy() implementation allows for program execution to continue in scenarios where a segmentation fault or crash should have occurred. The dangers occur in that subsequent execution and iterations of this code will be executed with this corrupted data.
Such as, we use 'memcpy' copy 0x80000000 byte to buffer(The buffer size is 100 bytes), it didn't crash.
The essence of the problem is that the memcpy implementation uses signed instructions. So, we use unsigned instructions instead of signed instructions.
Signed-off-by: Yan Zhu <zhuyan34@huawei.com>
---
sysdeps/arm/armv7/multiarch/memcpy_impl.S | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/sysdeps/arm/armv7/multiarch/memcpy_impl.S b/sysdeps/arm/armv7/multiarch/memcpy_impl.S
index bf4ac7077f..068474f0ea 100644
--- a/sysdeps/arm/armv7/multiarch/memcpy_impl.S
+++ b/sysdeps/arm/armv7/multiarch/memcpy_impl.S
@@ -268,7 +268,7 @@ ENTRY(memcpy)
mov dst, dstin /* Preserve dstin, we need to return it. */
cmp count, #64
- bge .Lcpy_not_short
+ bhs .Lcpy_not_short
/* Deal with small copies quickly by dropping straight into the
exit block. */
@@ -351,10 +351,10 @@ ENTRY(memcpy)
1:
subs tmp2, count, #64 /* Use tmp2 for count. */
- blt .Ltail63aligned
+ blo .Ltail63aligned
cmp tmp2, #512
- bge .Lcpy_body_long
+ bhs .Lcpy_body_long
.Lcpy_body_medium: /* Count in tmp2. */
#ifdef USE_VFP
@@ -378,7 +378,7 @@ ENTRY(memcpy)
add src, src, #64
vstr d1, [dst, #56]
add dst, dst, #64
- bge 1b
+ bhs 1b
tst tmp2, #0x3f
beq .Ldone
@@ -412,7 +412,7 @@ ENTRY(memcpy)
ldrd A_l, A_h, [src, #64]!
strd A_l, A_h, [dst, #64]!
subs tmp2, tmp2, #64
- bge 1b
+ bhs 1b
tst tmp2, #0x3f
bne 1f
ldr tmp2,[sp], #FRAME_SIZE
@@ -482,7 +482,7 @@ ENTRY(memcpy)
add src, src, #32
subs tmp2, tmp2, #prefetch_lines * 64 * 2
- blt 2f
+ blo 2f
1:
cpy_line_vfp d3, 0
cpy_line_vfp d4, 64
@@ -494,7 +494,7 @@ ENTRY(memcpy)
add dst, dst, #2 * 64
add src, src, #2 * 64
subs tmp2, tmp2, #prefetch_lines * 64
- bge 1b
+ bhs 1b
2:
cpy_tail_vfp d3, 0
--
2.12.3
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