diff options
| author | Roland Dreier <roland@purestorage.com> | 2012-07-17 02:34:24 +0400 |
|---|---|---|
| committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2012-07-17 04:35:36 +0400 |
| commit | b7fc7f3777582dea85156a821d78a522a0c083aa (patch) | |
| tree | fa190792d308e5fa42728d0d805e3338e1279ea0 /drivers/target | |
| parent | 1a5fa4576ec8a462313c7516b31d7453481ddbe8 (diff) | |
| download | linux-b7fc7f3777582dea85156a821d78a522a0c083aa.tar.xz | |
target: Fix possible integer underflow in UNMAP emulation
It's possible for an initiator to send us an UNMAP command with a
descriptor that is less than 8 bytes; in that case it's really bad for
us to set an unsigned int to that value, subtract 8 from it, and then
use that as a limit for our loop (since the value will wrap around to
a huge positive value).
Fix this by making size be signed and only looping if size >= 16 (ie
if we have at least a full descriptor available).
Also remove offset as an obfuscated name for the constant 8.
Signed-off-by: Roland Dreier <roland@purestorage.com>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target')
| -rw-r--r-- | drivers/target/target_core_iblock.c | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c index e6d08ee3166e..2efd70ca0b1d 100644 --- a/drivers/target/target_core_iblock.c +++ b/drivers/target/target_core_iblock.c @@ -325,24 +325,24 @@ static int iblock_execute_unmap(struct se_cmd *cmd) struct iblock_dev *ibd = dev->dev_ptr; unsigned char *buf, *ptr = NULL; sector_t lba; - unsigned int size = cmd->data_length, range; - int ret = 0, offset; - unsigned short dl, bd_dl; - - /* First UNMAP block descriptor starts at 8 byte offset */ - offset = 8; - size -= 8; + int size = cmd->data_length; + u32 range; + int ret = 0; + int dl, bd_dl; buf = transport_kmap_data_sg(cmd); dl = get_unaligned_be16(&buf[0]); bd_dl = get_unaligned_be16(&buf[2]); - ptr = &buf[offset]; - pr_debug("UNMAP: Sub: %s Using dl: %hu bd_dl: %hu size: %hu" + size = min(size - 8, bd_dl); + + /* First UNMAP block descriptor starts at 8 byte offset */ + ptr = &buf[8]; + pr_debug("UNMAP: Sub: %s Using dl: %u bd_dl: %u size: %u" " ptr: %p\n", dev->transport->name, dl, bd_dl, size, ptr); - while (size) { + while (size >= 16) { lba = get_unaligned_be64(&ptr[0]); range = get_unaligned_be32(&ptr[8]); pr_debug("UNMAP: Using lba: %llu and range: %u\n", |