cbcvebase.
CVE-2023-52452
published 2024-02-22

CVE-2023-52452: In the Linux kernel, the following vulnerability has been resolved: bpf: Fix accesses to uninit stack slots Privileged programs are supposed to be able to read…

PriorityP339high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.24%
15.1th percentile
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix accesses to uninit stack slots Privileged programs are supposed to be able to read uninitialized stack memory (ever since 6715df8d5) but, before this patch, these accesses were permitted inconsistently. In particular, accesses were permitted above state->allocated_stack, but not below it. In other words, if the stack was already "large enough", the access was permitted, but otherwise the access was rejected instead of being allowed to "grow the stack". This undesired rejection was happening in two places: - in check_stack_slot_within_bounds() - in check_stack_range_initialized() This patch arranges for these accesses to be permitted. A bunch of tests that were relying on the old rejection had to change; all of them were changed to add also run unprivileged, in which case the old behavior persists. One tests couldn't be updated - global_func16 - because it can't run unprivileged for other reasons. This patch also fixes the tracking of the stack size for variable-offset reads. This second fix is bundled in the same commit as the first one because they're inter-related. Before this patch, writes to the stack using registers containing a variable offset (as opposed to registers with fixed, known values) were not properly contributing to the function's needed stack size. As a result, it was possible for a program to verify, but then to attempt to read out-of-bounds data at runtime because a too small stack had been allocated for it. Each function tracks the size of the stack it needs in bpf_subprog_info.stack_depth, which is maintained by update_stack_depth(). For regular memory accesses, check_mem_access() was calling update_state_depth() but it was passing in only the fixed part of the offset register, ignoring the variable offset. This was incorrect; the minimum possible value of that register should be used instead. This tracking is now fixed by centralizing the tracking of stack size i

Affected

13 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.6.15-1 (forky)linux 6.6.15-1 (forky)
linuxlinux
linuxlinux
linuxlinux
linuxlinux>= 01f810ace9ed37255f27608a0864abebccf0aab3 < 0954982db8283016bf38e9db2da5adf47a102e190954982db8283016bf38e9db2da5adf47a102e19
linuxlinux>= 01f810ace9ed37255f27608a0864abebccf0aab3 < fbcf372c8eda2290470268e0afb5ab5d5f5d5fdefbcf372c8eda2290470268e0afb5ab5d5f5d5fde
linuxlinux>= 01f810ace9ed37255f27608a0864abebccf0aab3 < 6b4a64bafd107e521c01eec3453ce94a3fb385296b4a64bafd107e521c01eec3453ce94a3fb38529
linuxlinux>= 5.10.33 < 5.115.11
linuxlinux>= 5.11.17 < 5.125.12
linuxlinux_kernel>= 0 < 6.6.15-16.6.15-1
linuxlinux_kernel>= 0 < 6.6.15-16.6.15-1
linuxlinux_kernel>= 5.12 < 6.6.146.6.14
linuxlinux_kernel>= 6.7.0 < 6.7.26.7.2

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
osv7.8HIGH
vendor_debian7.8HIGH
vendor_redhat7.8HIGH
vendor_ubuntu6.5MEDIUM
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