pstore/zone: avoid dereferencing zero sized ptr after init zones

In psz_init_zones, if the requested area has a total_size less than
record_size, kcalloc will be called with c == 0 and will return
ZERO_SIZE_PTR.
Further, this will lead to an oops.

With this patch, in this scenario, it will look like this :
[    6.865545] pstore_zone:     total size : 28672 Bytes
[    6.865547] pstore_zone:     kmsg size : 65536 Bytes
[    6.865549] pstore_zone:     pmsg size : 0 Bytes
[    6.865551] pstore_zone:     console size : 0 Bytes
[    6.865553] pstore_zone:     ftrace size : 0 Bytes
[    6.872095] pstore_zone: zone dmesg total_size too small
[    6.878234] pstore_zone: alloc zones failed

Signed-off-by: Eugen Hristev <eugen.hristev@linaro.org>
Link: https://lore.kernel.org/r/20250110125714.2594719-1-eugen.hristev@linaro.org
Signed-off-by: Kees Cook <kees@kernel.org>
This commit is contained in:
Eugen Hristev 2025-01-10 14:57:14 +02:00 committed by Kees Cook
parent 542243af71
commit 067cdf0203

View File

@ -1212,6 +1212,11 @@ static struct pstore_zone **psz_init_zones(enum pstore_type_id type,
}
c = total_size / record_size;
if (unlikely(!c)) {
pr_err("zone %s total_size too small\n", name);
return ERR_PTR(-EINVAL);
}
zones = kcalloc(c, sizeof(*zones), GFP_KERNEL);
if (!zones) {
pr_err("allocate for zones %s failed\n", name);