[PATCH AUTOSEL 6.7 083/108] x86/cfi,bpf: Fix bpf_exception_cb() signature

Sasha Levin
2024-01-16T19:46:15Z

From: Alexei Starovoitov <alexei.starovoitov@gmail.com>

[ Upstream commit 852486b35f344887786d63250946dd921a05d7e8 ]

As per the earlier patches, BPF sub-programs have bpf_callback_t
signature and CFI expects callers to have matching signature. This is
violated by bpf_prog_aux::bpf_exception_cb().

[peterz: Changelog]
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/CAADnVQ+Z7UcXXBBhMubhcMM=R-dExk-uHtfOLtoLxQ1XxEpqEA@mail.gmail.com
Link: https://lore.kernel.org/r/20231215092707.910319166@infradead.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/bpf.h | 2 +-
kernel/bpf/helpers.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 741af9e5cb9d..8ebaaab5fdb5 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1442,7 +1442,7 @@ struct bpf_prog_aux {
int cgroup_atype; /* enum cgroup_bpf_attach_type */
struct bpf_map *cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE];
char name[BPF_OBJ_NAME_LEN];
- unsigned int (*bpf_exception_cb)(u64 cookie, u64 sp, u64 bp);
+ u64 (*bpf_exception_cb)(u64 cookie, u64 sp, u64 bp, u64, u64);
#ifdef CONFIG_SECURITY
void *security;
#endif
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index f43038931935..666e452230ed 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -2509,7 +2509,7 @@ __bpf_kfunc void bpf_throw(u64 cookie)
* which skips compiler generated instrumentation to do the same.
*/
kasan_unpoison_task_stack_below((void *)(long)ctx.sp);
- ctx.aux->bpf_exception_cb(cookie, ctx.sp, ctx.bp);
+ ctx.aux->bpf_exception_cb(cookie, ctx.sp, ctx.bp, 0, 0);
WARN(1, "A call to BPF exception callback should never return\n");
}

--
2.43.0