| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 207/343] kdb: do a sanity check on the cpu in kdb_per_cpu() | Date | Fri, 24 Jan 2020 10:30:25 +0100 |
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From: Dan Carpenter <dan.carpenter@oracle.com>
[ Upstream commit b586627e10f57ee3aa8f0cfab0d6f7dc4ae63760 ]
The "whichcpu" comes from argv[3]. The cpu_online() macro looks up the cpu in a bitmap of online cpus, but if the value is too high then it could read beyond the end of the bitmap and possibly Oops.
Fixes: 5d5314d6795f ("kdb: core for kgdb back end (1 of 2)") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- kernel/debug/kdb/kdb_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index 993db6b2348e7..15d902daeef6c 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -2634,7 +2634,7 @@ static int kdb_per_cpu(int argc, const char **argv) diag = kdbgetularg(argv[3], &whichcpu); if (diag) return diag; - if (!cpu_online(whichcpu)) { + if (whichcpu >= nr_cpu_ids || !cpu_online(whichcpu)) { kdb_printf("cpu %ld is not online\n", whichcpu); return KDB_BADCPUNUM; } -- 2.20.1
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