[ Upstream commit 9220c3ef6fefbf18f24aeedb1142a642b3de0596 ]
Commit 06744f2469 ("samples/bpf: Add openat2() enter/exit tracepoint
to syscall_tp sample") added two more eBPF programs to support the
openat2() syscall. However, it did not increase the size of the array
that holds the corresponding bpf_links. This leads to an out-of-bound
access on that array in the bpf_object__for_each_program loop and could
corrupt other variables on the stack. On our testing QEMU, it corrupts
the map1_fds array and causes the sample to fail:
# ./syscall_tp
prog #0: map ids 4 5
verify map:4 val: 5
map_lookup failed: Bad file descriptor
Dynamically allocate the array based on the number of programs reported
by libbpf to prevent similar inconsistencies in the future
Fixes: 06744f2469 ("samples/bpf: Add openat2() enter/exit tracepoint to syscall_tp sample")
Signed-off-by: Jinghao Jia <jinghao@linux.ibm.com>
Signed-off-by: Ruowen Qin <ruowenq2@illinois.edu>
Signed-off-by: Jinghao Jia <jinghao7@illinois.edu>
Link: https://lore.kernel.org/r/20230917214220.637721-4-jinghao7@illinois.edu
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
de4825a444