cbcvebase.
CVE-2024-50254
published 2024-11-09

CVE-2024-50254: In the Linux kernel, the following vulnerability has been resolved: bpf: Free dynamically allocated bits in bpf_iter_bits_destroy() bpf_iter_bits_destroy()…

PriorityP419medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.18%
7.2th percentile
In the Linux kernel, the following vulnerability has been resolved: bpf: Free dynamically allocated bits in bpf_iter_bits_destroy() bpf_iter_bits_destroy() uses "kit->nr_bits ] kmemleak_alloc+0x4b/0x80 [] __kmalloc_node_noprof+0x480/0x5c0 [] __alloc.isra.0+0x89/0xb0 [] alloc_bulk+0x2af/0x720 [] prefill_mem_cache+0x7f/0xb0 [] bpf_mem_alloc_init+0x3e2/0x610 [] bpf_global_ma_init+0x19/0x30 [] do_one_initcall+0xd3/0x3c0 [] kernel_init_freeable+0x66a/0x940 [] kernel_init+0x20/0x160 [] ret_from_fork+0x3c/0x70 [] ret_from_fork_asm+0x1a/0x30 That is because nr_bits will be set as zero in bpf_iter_bits_next() after all bits have been iterated. Fix the issue by setting kit->bit to kit->nr_bits instead of setting kit->nr_bits to zero when the iteration completes in bpf_iter_bits_next(). In addition, use "!nr_bits || bits >= nr_bits" to check whether the iteration is complete and still use "nr_bits > 64" to indicate whether bits are dynamically allocated. The "!nr_bits" check is necessary because bpf_iter_bits_new() may fail before setting kit->nr_bits, and this condition will stop the iteration early instead of accessing the zeroed or freed kit->bits. Considering the initial value of kit->bits is -1 and the type of kit->nr_bits is unsigned int, change the type of kit->nr_bits to int. The potential overflow problem will be handled in the following patch.

Affected

9 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.11.7-1 (forky)linux 6.11.7-1 (forky)
linuxlinux
linuxlinux>= 4665415975b0827e9646cab91c61d02a6b364d59 < 9cee266fafaf79fd465314546f637f9a3c2158309cee266fafaf79fd465314546f637f9a3c215830
linuxlinux>= 4665415975b0827e9646cab91c61d02a6b364d59 < 101ccfbabf4738041273ce64e2b116cf440dea13101ccfbabf4738041273ce64e2b116cf440dea13
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.11.7-16.11.7-1
linuxlinux_kernel>= 0 < 6.11.7-16.11.7-1
linuxlinux_kernel>= 0 < 6.11.0-18.186.11.0-18.18
linuxlinux_kernel>= 6.11 < 6.11.76.11.7

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.5MEDIUM
vendor_debian5.5LOW
vendor_redhat5.5MEDIUM
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