From 00d17cf342cd9f4f8fd1dcd79c8caec359145532 Mon Sep 17 00:00:00 2001 From: Konstantin Belousov Date: Fri, 3 Jun 2022 11:21:23 +0300 Subject: [PATCH] elf_note_prpsinfo: handle more failures from proc_getargv() Resulting sbuf_len() from proc_getargv() might return 0 if user mangled ps_strings enough. Also, sbuf_len() API contract is to return -1 if the buffer overflowed. The later should not occur because get_ps_strings() checks for catenated length, but check for this subtle detail explicitly as well to be more resilent. The end result is that p_comm is used in this situations. Approved by: so Security: FreeBSD-SA-22:09.elf Reported by: Josef 'Jeff' Sipek Reviewed by: delphij, markj admbugs: 988 Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D35391 --- sys/compat/linux/linux_elf.c | 9 ++++++--- sys/kern/imgact_elf.c | 11 +++++++---- 2 files changed, 13 insertions(+), 7 deletions(-) diff --git a/sys/compat/linux/linux_elf.c b/sys/compat/linux/linux_elf.c index bcbd4d1cad51..b02b6e2cc777 100644 --- a/sys/compat/linux/linux_elf.c +++ b/sys/compat/linux/linux_elf.c @@ -155,13 +155,16 @@ __linuxN(note_prpsinfo)(void *arg, struct sbuf *sb, size_t *sizep) sizeof(psinfo->pr_psargs), SBUF_FIXEDLEN); error = proc_getargv(curthread, p, &sbarg); PRELE(p); - if (sbuf_finish(&sbarg) == 0) + if (sbuf_finish(&sbarg) == 0) { len = sbuf_len(&sbarg) - 1; - else + if (len > 0) + len--; + } else { len = sizeof(psinfo->pr_psargs) - 1; + } sbuf_delete(&sbarg); } - if (error || len == 0) + if (error != 0 || len == 0 || (ssize_t)len == -1) strlcpy(psinfo->pr_psargs, p->p_comm, sizeof(psinfo->pr_psargs)); else { diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c index ca4c59089775..38be7d100ae9 100644 --- a/sys/kern/imgact_elf.c +++ b/sys/kern/imgact_elf.c @@ -2205,13 +2205,16 @@ __elfN(note_prpsinfo)(void *arg, struct sbuf *sb, size_t *sizep) sizeof(psinfo->pr_psargs), SBUF_FIXEDLEN); error = proc_getargv(curthread, p, &sbarg); PRELE(p); - if (sbuf_finish(&sbarg) == 0) - len = sbuf_len(&sbarg) - 1; - else + if (sbuf_finish(&sbarg) == 0) { + len = sbuf_len(&sbarg); + if (len > 0) + len--; + } else { len = sizeof(psinfo->pr_psargs) - 1; + } sbuf_delete(&sbarg); } - if (error || len == 0) + if (error != 0 || len == 0 || (ssize_t)len == -1) strlcpy(psinfo->pr_psargs, p->p_comm, sizeof(psinfo->pr_psargs)); else {