libbpf: harden parse_vma_segs() path parsing#12164
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libbpf: harden parse_vma_segs() path parsing#12164kernel-patches-daemon-bpf[bot] wants to merge 1 commit into
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parse_vma_segs() in tools/lib/bpf/usdt.c parses /proc/<pid>/maps
with two widthless scansets, "%s" into mode[16] and "%[^\n]"
into line[4096]. A VMA name in maps is not limited to that local
buffer; a deeply nested backing path can produce a maps record long
enough to overflow the stack buffer.
Bound both scansets to the declared buffer sizes ("%15s" for mode[16]
and "%4095[^\n]" for line[4096]) and drain any residue past line[4094]
with "%*[^\n]" before the trailing "\n". Without the drain, the residue
of an over-long record would stay in the stream and break the next
"%zx-%zx" parse, so the loop would exit early and silently skip later
maps records.
Also stop using sscanf(..., "%s") to peel the /proc/<pid>/root prefix
from lib_path. Parse the pid and prefix length with "%n", check for the
following slash, and copy the remainder with libbpf_strlcpy(). That
removes a second unbounded stack write and preserves paths containing
spaces.
Fixes: 74cc631 ("libbpf: Add USDT notes parsing and resolution logic")
Cc: stable@vger.kernel.org
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Author
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Upstream branch: b1fcdf9 |
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Pull request for series with
subject: libbpf: harden parse_vma_segs() path parsing
version: 4
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=1099600