On 11.11.21 11:03, David Hildenbrand wrote: > On 08.11.21 09:38, Yafang Shao wrote: >> It is better to use get_task_comm() instead of the open coded string >> copy as we do in other places. >> >> struct elf_prpsinfo is used to dump the task information in userspace >> coredump or kernel vmcore. Below is the verfication of vmcore, >> >> crash> ps >> PID PPID CPU TASK ST %MEM VSZ RSS COMM >> 0 0 0 ffffffff9d21a940 RU 0.0 0 0 [swapper/0] >>> 0 0 1 ffffa09e40f85e80 RU 0.0 0 0 [swapper/1] >>> 0 0 2 ffffa09e40f81f80 RU 0.0 0 0 [swapper/2] >>> 0 0 3 ffffa09e40f83f00 RU 0.0 0 0 [swapper/3] >>> 0 0 4 ffffa09e40f80000 RU 0.0 0 0 [swapper/4] >>> 0 0 5 ffffa09e40f89f80 RU 0.0 0 0 [swapper/5] >> 0 0 6 ffffa09e40f8bf00 RU 0.0 0 0 [swapper/6] >>> 0 0 7 ffffa09e40f88000 RU 0.0 0 0 [swapper/7] >>> 0 0 8 ffffa09e40f8de80 RU 0.0 0 0 [swapper/8] >>> 0 0 9 ffffa09e40f95e80 RU 0.0 0 0 [swapper/9] >>> 0 0 10 ffffa09e40f91f80 RU 0.0 0 0 [swapper/10] >>> 0 0 11 ffffa09e40f93f00 RU 0.0 0 0 [swapper/11] >>> 0 0 12 ffffa09e40f90000 RU 0.0 0 0 [swapper/12] >>> 0 0 13 ffffa09e40f9bf00 RU 0.0 0 0 [swapper/13] >>> 0 0 14 ffffa09e40f98000 RU 0.0 0 0 [swapper/14] >>> 0 0 15 ffffa09e40f9de80 RU 0.0 0 0 [swapper/15] >> >> It works well as expected. >> >> Suggested-by: Kees Cook <keescook@xxxxxxxxxxxx> >> Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx> >> Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> >> Cc: Arnaldo Carvalho de Melo <arnaldo.melo@xxxxxxxxx> >> Cc: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> >> Cc: Michal Miroslaw <mirq-linux@xxxxxxxxxxxx> >> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> >> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> >> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> >> Cc: David Hildenbrand <david@xxxxxxxxxx> >> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> >> Cc: Kees Cook <keescook@xxxxxxxxxxxx> >> Cc: Petr Mladek <pmladek@xxxxxxxx> >> --- >> fs/binfmt_elf.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c >> index a813b70f594e..138956fd4a88 100644 >> --- a/fs/binfmt_elf.c >> +++ b/fs/binfmt_elf.c >> @@ -1572,7 +1572,7 @@ static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p, >> SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid)); >> SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid)); >> rcu_read_unlock(); >> - strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname)); >> + get_task_comm(psinfo->pr_fname, p); >> >> return 0; >> } >> > > We have a hard-coded "pr_fname[16]" as well, not sure if we want to > adjust that to use TASK_COMM_LEN? But if the intention is to chance TASK_COMM_LEN later, we might want to keep that unchanged. (replacing the 16 by a define might still be a good idea, similar to how it's done for ELF_PRARGSZ, but just a thought) -- Thanks, David / dhildenb
