When we dynamically generate a name for a configuration in get-reg-list we use strcat() to append to a buffer allocated using malloc() but we never initialise that buffer. Since malloc() offers no guarantees regarding the contents of the memory it returns this can lead to us corrupting, and likely overflowing, the buffer: vregs: PASS vregs+pmu: PASS sve: PASS sve+pmu: PASS vregs+pauth_address+pauth_generic: PASS X�vr+gspauth_addre+spauth_generi+pmu: PASS Initialise the buffer to an empty string to avoid this. Fixes: 2f9ace5d4557 ("KVM: arm64: selftests: get-reg-list: Introduce vcpu configs") Reviewed-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx> Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> --- Changes in v3: - Rebase this bugfix onto v6.7-rc1 - Link to v2: https://lore.kernel.org/r/20231017-kvm-get-reg-list-str-init-v2-1-ee30b1df3e50@xxxxxxxxxx Changes in v2: - Update Fixes: tag. - Link to v1: https://lore.kernel.org/r/20231013-kvm-get-reg-list-str-init-v1-1-034f370ff8ab@xxxxxxxxxx --- tools/testing/selftests/kvm/get-reg-list.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/kvm/get-reg-list.c b/tools/testing/selftests/kvm/get-reg-list.c index be7bf5224434..dd62a6976c0d 100644 --- a/tools/testing/selftests/kvm/get-reg-list.c +++ b/tools/testing/selftests/kvm/get-reg-list.c @@ -67,6 +67,7 @@ static const char *config_name(struct vcpu_reg_list *c) c->name = malloc(len); + c->name[0] = '\0'; len = 0; for_each_sublist(c, s) { if (!strcmp(s->name, "base")) --- base-commit: b85ea95d086471afb4ad062012a4d73cd328fa86 change-id: 20231012-kvm-get-reg-list-str-init-76c8ed4e19d6 Best regards, -- Mark Brown <broonie@xxxxxxxxxx>