From: Peter Maydell Date: Fri, 3 Mar 2017 15:50:31 +0000 (+0000) Subject: disas/microblaze: Avoid unintended sign extension X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=1d153a3388b150b8aeedde32242db86b79c45473;p=qemu.git disas/microblaze: Avoid unintended sign extension In read_insn_microblaze() we assemble 4 bytes into an 'unsigned long'. If 'unsigned long' is 64 bits and the high byte has its top bit set, then C's implicit conversion from 'unsigned char' to 'int' for the shift will result in an unintended sign extension which sets the top 32 bits in 'inst'. Add casts to prevent this. (Spotted by Coverity, CID 1005401.) Signed-off-by: Peter Maydell Reviewed-by: Edgar E. Iglesias Message-id: 1488556233-31246-5-git-send-email-peter.maydell@linaro.org --- diff --git a/disas/microblaze.c b/disas/microblaze.c index 91b30acbe1..407c0a3ffa 100644 --- a/disas/microblaze.c +++ b/disas/microblaze.c @@ -748,9 +748,11 @@ read_insn_microblaze (bfd_vma memaddr, } if (info->endian == BFD_ENDIAN_BIG) - inst = (ibytes[0] << 24) | (ibytes[1] << 16) | (ibytes[2] << 8) | ibytes[3]; + inst = ((unsigned)ibytes[0] << 24) | (ibytes[1] << 16) + | (ibytes[2] << 8) | ibytes[3]; else if (info->endian == BFD_ENDIAN_LITTLE) - inst = (ibytes[3] << 24) | (ibytes[2] << 16) | (ibytes[1] << 8) | ibytes[0]; + inst = ((unsigned)ibytes[3] << 24) | (ibytes[2] << 16) + | (ibytes[1] << 8) | ibytes[0]; else abort ();