kernel/linux.git, branch v3.2.82

Linux 3.2.82

2016-08-22T21:37:20+00:00

audit: fix a double fetch in audit_log_single_execve_arg()

2016-08-22T21:37:19+00:00

commit 43761473c254b45883a64441dd0bc85a42f3645c upstream. There is a double fetch problem in audit_log_single_execve_arg() where we first check the execve(2) argumnets for any "bad" characters which would require hex encoding and then re-fetch the arguments for logging in the audit record[1]. Of course this leaves a window of opportunity for an unsavory application to munge with the data. This patch reworks things by only fetching the argument data once[2] into a buffer where it is scanned and logged into the audit records(s). In addition to fixing the double fetch, this patch improves on the original code in a few other ways: better handling of large arguments which require encoding, stricter record length checking, and some performance improvements (completely unverified, but we got rid of some strlen() calls, that's got to be a good thing). As part of the development of this patch, I've also created a basic regression test for the audit-testsuite, the test can be tracked on GitHub at the following link: * https://github.com/linux-audit/audit-testsuite/issues/25 [1] If you pay careful attention, there is actually a triple fetch problem due to a strnlen_user() call at the top of the function. [2] This is a tiny white lie, we do make a call to strnlen_user() prior to fetching the argument data. I don't like it, but due to the way the audit record is structured we really have no choice unless we copy the entire argument at once (which would require a rather wasteful allocation). The good news is that with this patch the kernel no longer relies on this strnlen_user() value for anything beyond recording it in the log, we also update it with a trustworthy value whenever possible. Reported-by: Pengfei Wang Signed-off-by: Paul Moore [bwh: Backported to 3.2: - In audit_log_execve_info() various information is retrieved via the extra parameter struct audit_aux_data_execve *axi - Adjust context] Signed-off-by: Ben Hutchings

tcp: make challenge acks less predictable

2016-08-22T21:37:19+00:00

commit 75ff39ccc1bd5d3c455b6822ab09e533c551f758 upstream. Yue Cao claims that current host rate limiting of challenge ACKS (RFC 5961) could leak enough information to allow a patient attacker to hijack TCP sessions. He will soon provide details in an academic paper. This patch increases the default limit from 100 to 1000, and adds some randomization so that the attacker can no longer hijack sessions without spending a considerable amount of probes. Based on initial analysis and patch from Linus. Note that we also have per socket rate limiting, so it is tempting to remove the host limit in the future. v2: randomize the count of challenge acks per second, not the period. Fixes: 282f23c6ee34 ("tcp: implement RFC 5961 3.2") Reported-by: Yue Cao Signed-off-by: Eric Dumazet Suggested-by: Linus Torvalds Cc: Yuchung Cheng Cc: Neal Cardwell Acked-by: Neal Cardwell Acked-by: Yuchung Cheng Signed-off-by: David S. Miller [bwh: Backported to 3.2: - Adjust context - Use ACCESS_ONCE() instead of {READ,WRITE}_ONCE() - Open-code prandom_u32_max()] Signed-off-by: Ben Hutchings

rds: fix an infoleak in rds_inc_info_copy

2016-08-22T21:37:19+00:00

commit 4116def2337991b39919f3b448326e21c40e0dbb upstream. The last field "flags" of object "minfo" is not initialized. Copying this object out may leak kernel stack data. Assign 0 to it to avoid leak. Signed-off-by: Kangjie Lu Acked-by: Santosh Shilimkar Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings

tipc: fix an infoleak in tipc_nl_compat_link_dump

2016-08-22T21:37:19+00:00

commit 5d2be1422e02ccd697ccfcd45c85b4a26e6178e2 upstream. link_info.str is a char array of size 60. Memory after the NULL byte is not initialized. Sending the whole object out can cause a leak. Signed-off-by: Kangjie Lu Signed-off-by: David S. Miller [bwh: Backported to 3.2: the unpadded strcpy() is in tipc_node_get_links() and no nlattr is involved, so use strncpy()] Signed-off-by: Ben Hutchings

ALSA: timer: Fix leak in events via snd_timer_user_tinterrupt

2016-08-22T21:37:19+00:00

commit e4ec8cc8039a7063e24204299b462bd1383184a5 upstream. The stack object “r1” has a total size of 32 bytes. Its field “event” and “val” both contain 4 bytes padding. These 8 bytes padding bytes are sent to user without being initialized. Signed-off-by: Kangjie Lu Signed-off-by: Takashi Iwai Signed-off-by: Ben Hutchings

ALSA: timer: Fix leak in events via snd_timer_user_ccallback

2016-08-22T21:37:19+00:00

commit 9a47e9cff994f37f7f0dbd9ae23740d0f64f9fe6 upstream. The stack object “r1” has a total size of 32 bytes. Its field “event” and “val” both contain 4 bytes padding. These 8 bytes padding bytes are sent to user without being initialized. Signed-off-by: Kangjie Lu Signed-off-by: Takashi Iwai Signed-off-by: Ben Hutchings

ALSA: timer: Fix leak in SNDRV_TIMER_IOCTL_PARAMS

2016-08-22T21:37:18+00:00

commit cec8f96e49d9be372fdb0c3836dcf31ec71e457e upstream. The stack object “tread” has a total size of 32 bytes. Its field “event” and “val” both contain 4 bytes padding. These 8 bytes padding bytes are sent to user without being initialized. Signed-off-by: Kangjie Lu Signed-off-by: Takashi Iwai Signed-off-by: Ben Hutchings

USB: usbfs: fix potential infoleak in devio

2016-08-22T21:37:18+00:00

commit 681fef8380eb818c0b845fca5d2ab1dcbab114ee upstream. The stack object “ci” has a total size of 8 bytes. Its last 3 bytes are padding bytes which are not initialized and leaked to userland via “copy_to_user”. Signed-off-by: Kangjie Lu Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings

proc: prevent stacking filesystems on top

2016-08-22T21:37:18+00:00

commit e54ad7f1ee263ffa5a2de9c609d58dfa27b21cd9 upstream. This prevents stacking filesystems (ecryptfs and overlayfs) from using procfs as lower filesystem. There is too much magic going on inside procfs, and there is no good reason to stack stuff on top of procfs. (For example, procfs does access checks in VFS open handlers, and ecryptfs by design calls open handlers from a kernel thread that doesn't drop privileges or so.) Signed-off-by: Jann Horn Signed-off-by: Linus Torvalds [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings