Re: [PATCH] fprobe: Fix to allocate entry_data_size buffer with rethook instances
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Date: 2024-02-29 11:28:19
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On Thu, 29 Feb 2024 20:22:47 +0900 "Masami Hiramatsu (Google)" [off-list ref] wrote:
From: Masami Hiramatsu (Google) <mhiramat@kernel.org> Fix to allocate fprobe::entry_data_size buffer with rethook instances. If fprobe doesn't allocate entry_data_size buffer for each rethook instance, fprobe entry handler can cause a buffer overrun when storing entry data in entry handler.
Oops, missed a URL.
Reported-by: Jiri Olsa <redacted>
Closes: https://lore.kernel.org/all/Zd9eBn2FTQzYyg7L@krava/ (local) Thanks,
quoted hunk ↗ jump to hunk
Fixes: 4bbd93455659 ("kprobes: kretprobe scalability improvement") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> --- kernel/trace/fprobe.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-)diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c index 6cd2a4e3afb8..9ff018245840 100644 --- a/kernel/trace/fprobe.c +++ b/kernel/trace/fprobe.c@@ -189,9 +189,6 @@ static int fprobe_init_rethook(struct fprobe *fp, int num) { int size; - if (num <= 0) - return -EINVAL; - if (!fp->exit_handler) { fp->rethook = NULL; return 0;@@ -199,15 +196,16 @@ static int fprobe_init_rethook(struct fprobe *fp, int num) /* Initialize rethook if needed */ if (fp->nr_maxactive) - size = fp->nr_maxactive; + num = fp->nr_maxactive; else - size = num * num_possible_cpus() * 2; - if (size <= 0) + num *= num_possible_cpus() * 2; + if (num <= 0) return -EINVAL; + size = sizeof(struct fprobe_rethook_node) + fp->entry_data_size; + /* Initialize rethook */ - fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler, - sizeof(struct fprobe_rethook_node), size); + fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler, size, num); if (IS_ERR(fp->rethook)) return PTR_ERR(fp->rethook);
-- Masami Hiramatsu (Google) [off-list ref]