arm: CVE-2020-6096: Fix multiarch memcpy for negative length [BZ #25620]

Unsigned branch instructions could be used for r2 to fix the wrong
behavior when a negative length is passed to memcpy.
This commit fixes the armv7 version.

diff --git a/sysdeps/arm/armv7/multiarch/memcpy_impl.S b/sysdeps/arm/armv7/multiarch/memcpy_impl.S
index bf4ac70..379bb56 100644 (file)
--- 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
@@ -615,8 +615,8 @@ ENTRY(memcpy)
 1:
        pld     [src, #(3 * 64)]
        subs    count, count, #64
-       ldrmi   tmp2, [sp], #FRAME_SIZE
-       bmi     .Ltail63unaligned
+       ldrlo   tmp2, [sp], #FRAME_SIZE
+       blo     .Ltail63unaligned
        pld     [src, #(4 * 64)]
 
 #ifdef USE_NEON
@@ -633,7 +633,7 @@ ENTRY(memcpy)
        neon_load_multi d0-d3, src
        neon_load_multi d4-d7, src
        subs    count, count, #64
-       bmi     2f
+       blo     2f
 1:
        pld     [src, #(4 * 64)]
        neon_store_multi d0-d3, dst
@@ -641,7 +641,7 @@ ENTRY(memcpy)
        neon_store_multi d4-d7, dst
        neon_load_multi d4-d7, src
        subs    count, count, #64
-       bpl     1b
+       bhs     1b
 2:
        neon_store_multi d0-d3, dst
        neon_store_multi d4-d7, dst