CVE-2024-35911

In the Linux kernel, the following vulnerability has been resolved:

ice: fix memory corruption bug with suspend and rebuild

The ice driver would previously panic after suspend. This is caused from the driver only calling the ice_vsi_free_q_vectors() function by itself, when it is suspending. Since commit b3e7b3a6ee92 (ice: prevent NULL pointer deref during reload) the driver has zeroed out num_q_vectors, and only restored it in ice_vsi_cfg_def().

This further causes the ice_rebuild() function to allocate a zero length buffer, after which num_q_vectors is updated, and then the new value of num_q_vectors is used to index into the zero length buffer, which corrupts memory.

The fix entails making sure all the code referencing num_q_vectors only does so after it has been reset via ice_vsi_cfg_def().

I didnt perform a full bisect, but I was able to test against 6.1.77 kernel and that ice driver works fine for suspend/resume with no panic, so sometime since then, this problem was introduced.

Also clean up an un-needed init of a local variable in the function being modified.

PANIC from 6.8.0-rc1:

[1026674.915596] PM: suspend exit [1026675.664697] ice 0000:17:00.1: PTP reset successful [1026675.664707] ice 0000:17:00.1: 2755 msecs passed between update to cached PHC time [1026675.667660] ice 0000:b1:00.0: PTP reset successful [1026675.675944] ice 0000:b1:00.0: 2832 msecs passed between update to cached PHC time [1026677.137733] ixgbe 0000:31:00.0 ens787: NIC Link is Up 1 Gbps, Flow Control: None [1026677.190201] BUG: kernel NULL pointer dereference, address: 0000000000000010 [1026677.192753] ice 0000:17:00.0: PTP reset successful [1026677.192764] ice 0000:17:00.0: 4548 msecs passed between update to cached PHC time [1026677.197928] #PF: supervisor read access in kernel mode [1026677.197933] #PF: error_code(0x0000) - not-present page [1026677.197937] PGD 1557a7067 P4D 0 [1026677.212133] ice 0000:b1:00.1: PTP reset successful [1026677.212143] ice 0000:b1:00.1: 4344 msecs passed between update to cached PHC time [1026677.212575] [1026677.243142] Oops: 0000 [#1] PREEMPT SMP NOPTI [1026677.247918] CPU: 23 PID: 42790 Comm: kworker/23:0 Kdump: loaded Tainted: G W 6.8.0-rc1+ #1 [1026677.257989] Hardware name: Intel Corporation M50CYP2SBSTD/M50CYP2SBSTD, BIOS SE5C620.86B.01.01.0005.2202160810 02/16/2022 [1026677.269367] Workqueue: ice ice_service_task [ice] [1026677.274592] RIP: 0010:ice_vsi_rebuild_set_coalesce+0x130/0x1e0 [ice] [1026677.281421] Code: 0f 84 3a ff ff ff 41 0f b7 74 ec 02 66 89 b0 22 02 00 00 81 e6 ff 1f 00 00 e8 ec fd ff ff e9 35 ff ff ff 48 8b 43 30 49 63 ed <41> 0f b7 34 24 41 83 c5 01 48 8b 3c e8 66 89 b7 aa 02 00 00 81 e6 [1026677.300877] RSP: 0018:ff3be62a6399bcc0 EFLAGS: 00010202 [1026677.306556] RAX: ff28691e28980828 RBX: ff28691e41099828 RCX: 0000000000188000 [1026677.314148] RDX: 0000000000000000 RSI: 0000000000000010 RDI: ff28691e41099828 [1026677.321730] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [1026677.329311] R10: 0000000000000007 R11: ffffffffffffffc0 R12: 0000000000000010 [1026677.336896] R13: 0000000000000000 R14: 0000000000000000 R15: ff28691e0eaa81a0 [1026677.344472] FS: 0000000000000000(0000) GS:ff28693cbffc0000(0000) knlGS:0000000000000000 [1026677.353000] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [1026677.359195] CR2: 0000000000000010 CR3: 0000000128df4001 CR4: 0000000000771ef0 [1026677.366779] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [1026677.374369] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [1026677.381952] PKRU: 55555554 [1026677.385116] Call Trace: [1026677.388023] [1026677.390589] ? __die+0x20/0x70 [1026677.394105] ? page_fault_oops+0x82/0x160 [1026677.398576] ? do_user_addr_fault+0x65/0x6a0 [1026677.403307] ? exc_page_fault+0x6a/0x150 [1026677.407694] ? asm_exc_page_fault+0x22/0x30 [1026677.412349] ? ice_vsi_rebuild_set_coalesce+0x130/0x1e0 [ice] [1026677.4186 —truncated—

Weakness

The product writes data past the end, or before the beginning, of the intended buffer.

Affected Software

Potential Mitigations

• Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

• For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer.

• Be wary that a language’s interface to native code may still be subject to overflows, even if the language itself is theoretically safe.

• Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

• Examples include the Safe C String Library (SafeStr) by Messier and Viega [REF-57], and the Strsafe.h library from Microsoft [REF-56]. These libraries provide safer versions of overflow-prone string-handling functions.

• Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking.

• D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.

• Consider adhering to the following rules when allocating and managing an application’s memory:

• Run or compile the software using features or extensions that randomly arrange the positions of a program’s executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code.

• Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as “rebasing” (for Windows) and “prelinking” (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking.

• For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].

• Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX [REF-60] [REF-61]. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment.

• For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND [REF-1336].

References

• https://git.kernel.org/stable/c/11ff8392943e08a35cb0aa19d638b02db745f170
• https://git.kernel.org/stable/c/1cb7fdb1dfde1aab66780b4ba44dba6402172111
• https://git.kernel.org/stable/c/e40a02f06ceb0e0b0183e0b973ac5dbf8f75edec
• https://git.kernel.org/stable/c/11ff8392943e08a35cb0aa19d638b02db745f170
• https://git.kernel.org/stable/c/1cb7fdb1dfde1aab66780b4ba44dba6402172111
• https://git.kernel.org/stable/c/e40a02f06ceb0e0b0183e0b973ac5dbf8f75edec