From beea361050728138b82c57dda0c4810402d342b9 Mon Sep 17 00:00:00 2001 From: Alexander Anisimov Date: Wed, 8 Jul 2020 14:18:31 +0200 Subject: [PATCH 2/2] 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. CVE: CVE-2020-6096 Upstream-Status: Backport [git://sourceware.org/git/glibc.git] Signed-off-by: Zhixiong Chi --- sysdeps/arm/armv7/multiarch/memcpy_impl.S | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/sysdeps/arm/armv7/multiarch/memcpy_impl.S b/sysdeps/arm/armv7/multiarch/memcpy_impl.S index bf4ac7077f..379bb56fc9 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 @@ -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 -- 2.17.0