Bug 462281
| Summary: | kernel: netlink: fix overrun in attribute iteration | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Product: | [Other] Security Response | Reporter: | Eugene Teo (Security Response) <eteo> | ||||||
| Component: | vulnerability | Assignee: | Red Hat Product Security <security-response-team> | ||||||
| Status: | CLOSED ERRATA | QA Contact: | |||||||
| Severity: | medium | Docs Contact: | |||||||
| Priority: | medium | ||||||||
| Version: | unspecified | CC: | bhu, kseifried, lgoncalv, lwang, williams | ||||||
| Target Milestone: | --- | ||||||||
| Target Release: | --- | ||||||||
| Hardware: | All | ||||||||
| OS: | Linux | ||||||||
| Whiteboard: | |||||||||
| Fixed In Version: | Doc Type: | Bug Fix | |||||||
| Doc Text: | Story Points: | --- | |||||||
| Clone Of: | Environment: | ||||||||
| Last Closed: | 2011-09-30 19:37:07 UTC | Type: | --- | ||||||
| Regression: | --- | Mount Type: | --- | ||||||
| Documentation: | --- | CRM: | |||||||
| Verified Versions: | Category: | --- | |||||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||||
| Embargoed: | |||||||||
| Bug Depends On: | 462282, 462283 | ||||||||
| Bug Blocks: | |||||||||
| Attachments: |
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Proposed upstream patch: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=1045b03e07d85f3545118510a587035536030c1c Created attachment 316712 [details]
Upstream patch for this issue
(In reply to comment #0) > Description of problem: > From: Vegard Nossum <vegard.nossum> > > kmemcheck reported this: > > kmemcheck: Caught 16-bit read from uninitialized memory (f6c1ba30) > 0500110001508abf050010000500000002017300140000006f72672e66726565 > i i i i i i i i i i i i i u u u u u u u u u u u u u u u u u u u > ^ > Pid: 3462, comm: wpa_supplicant Not tainted (2.6.27-rc3-00054-g6397ab9-dirty > #13) man wpa_supplicant - wpa_supplicant is designed to be a "daemon" program that runs in the background and acts as the backend component controlling the wire-less connection. wpa_supplicant supports separate frontend programs and an example text-based frontend, wpa_cli, is included with wpa_supplicant. Created attachment 316713 [details]
Proposed backported patch for MRG kernel
The Patch for MRG was added in -82 |
Description of problem: From: Vegard Nossum <vegard.nossum> kmemcheck reported this: kmemcheck: Caught 16-bit read from uninitialized memory (f6c1ba30) 0500110001508abf050010000500000002017300140000006f72672e66726565 i i i i i i i i i i i i i u u u u u u u u u u u u u u u u u u u ^ Pid: 3462, comm: wpa_supplicant Not tainted (2.6.27-rc3-00054-g6397ab9-dirty #13) EIP: 0060:[<c05de64a>] EFLAGS: 00010296 CPU: 0 EIP is at nla_parse+0x5a/0xf0 EAX: 00000008 EBX: fffffffd ECX: c06f16c0 EDX: 00000005 ESI: 00000010 EDI: f6c1ba30 EBP: f6367c6c ESP: c0a11e88 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 CR0: 8005003b CR2: f781cc84 CR3: 3632f000 CR4: 000006d0 DR0: c0ead9bc DR1: 00000000 DR2: 00000000 DR3: 00000000 DR6: ffff4ff0 DR7: 00000400 [<c05d4b23>] rtnl_setlink+0x63/0x130 [<c05d5f75>] rtnetlink_rcv_msg+0x165/0x200 [<c05ddf66>] netlink_rcv_skb+0x76/0xa0 [<c05d5dfe>] rtnetlink_rcv+0x1e/0x30 [<c05dda21>] netlink_unicast+0x281/0x290 [<c05ddbe9>] netlink_sendmsg+0x1b9/0x2b0 [<c05beef2>] sock_sendmsg+0xd2/0x100 [<c05bf945>] sys_sendto+0xa5/0xd0 [<c05bf9a6>] sys_send+0x36/0x40 [<c05c03d6>] sys_socketcall+0x1e6/0x2c0 [<c020353b>] sysenter_do_call+0x12/0x3f [<ffffffff>] 0xffffffff This is the line in nla_ok(): /** * nla_ok - check if the netlink attribute fits into the remaining bytes * @nla: netlink attribute * @remaining: number of bytes remaining in attribute stream */ static inline int nla_ok(const struct nlattr *nla, int remaining) { return remaining >= sizeof(*nla) && nla->nla_len >= sizeof(*nla) && nla->nla_len <= remaining; } It turns out that remaining can become negative due to alignment in nla_next(). But GCC promotes "remaining" to unsigned in the test against sizeof(*nla) above. Therefore the test succeeds, and the nla_for_each_attr() may access memory outside the received buffer. A short example illustrating this point is here: #include <stdio.h> main(void) { printf("%d\n", -1 >= sizeof(int)); } ...which prints "1".