6.7-stable review patch. If anyone has any objections, please let me know.
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From: Masami Hiramatsu (Google) mhiramat@kernel.org
commit 6572786006fa96ad2c35bb31757f1f861298093b upstream.
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.
Link: https://lore.kernel.org/all/170920576727.107552.638161246679734051.stgit@dev...
Reported-by: Jiri Olsa olsajiri@gmail.com Closes: https://lore.kernel.org/all/Zd9eBn2FTQzYyg7L@krava/ Fixes: 4bbd93455659 ("kprobes: kretprobe scalability improvement") Cc: stable@vger.kernel.org Tested-by: Jiri Olsa olsajiri@gmail.com Signed-off-by: Masami Hiramatsu (Google) mhiramat@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.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);