From 2b82c57e399700f5134c47d86d45ef2f2bd465e2 Mon Sep 17 00:00:00 2001 From: Mark Johnston Date: Wed, 28 Jul 2021 10:16:25 -0400 Subject: [PATCH] pf: Initialize arrays before copying out to userland A number of pf ioctls populate an array of structures and copy it out. They have the following structures: - caller specifies the size of its output buffer - ioctl handler allocates a kernel buffer of the same size - ioctl handler populates the buffer, possibly leaving some items initialized if the caller provided more space than needed - ioctl handler copies the entire buffer out to userland Thus, if more space was provided than is required, we end up copying out uninitialized kernel memory. Simply zero the buffer at allocation time to prevent this. Reported by: KMSAN Reviewed by: kp MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D31313 --- sys/netpfil/pf/pf_ioctl.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/sys/netpfil/pf/pf_ioctl.c b/sys/netpfil/pf/pf_ioctl.c index 33c38eaaf9f..3dc52da0560 100644 --- a/sys/netpfil/pf/pf_ioctl.c +++ b/sys/netpfil/pf/pf_ioctl.c @@ -3824,7 +3824,7 @@ DIOCCHANGEADDR_error: totlen = io->pfrio_size * sizeof(struct pfr_table); pfrts = mallocarray(io->pfrio_size, sizeof(struct pfr_table), - M_TEMP, M_NOWAIT); + M_TEMP, M_NOWAIT | M_ZERO); if (pfrts == NULL) { error = ENOMEM; PF_RULES_RUNLOCK(); @@ -3862,7 +3862,7 @@ DIOCCHANGEADDR_error: totlen = io->pfrio_size * sizeof(struct pfr_tstats); pfrtstats = mallocarray(io->pfrio_size, - sizeof(struct pfr_tstats), M_TEMP, M_NOWAIT); + sizeof(struct pfr_tstats), M_TEMP, M_NOWAIT | M_ZERO); if (pfrtstats == NULL) { error = ENOMEM; PF_RULES_RUNLOCK(); @@ -4094,7 +4094,7 @@ DIOCCHANGEADDR_error: } totlen = io->pfrio_size * sizeof(struct pfr_addr); pfras = mallocarray(io->pfrio_size, sizeof(struct pfr_addr), - M_TEMP, M_WAITOK); + M_TEMP, M_WAITOK | M_ZERO); PF_RULES_RLOCK(); error = pfr_get_addrs(&io->pfrio_table, pfras, &io->pfrio_size, io->pfrio_flags | PFR_FLAG_USERIOCTL); @@ -4122,7 +4122,7 @@ DIOCCHANGEADDR_error: } totlen = io->pfrio_size * sizeof(struct pfr_astats); pfrastats = mallocarray(io->pfrio_size, - sizeof(struct pfr_astats), M_TEMP, M_WAITOK); + sizeof(struct pfr_astats), M_TEMP, M_WAITOK | M_ZERO); PF_RULES_RLOCK(); error = pfr_get_astats(&io->pfrio_table, pfrastats, &io->pfrio_size, io->pfrio_flags | PFR_FLAG_USERIOCTL); @@ -4626,7 +4626,7 @@ DIOCCHANGEADDR_error: bufsiz = io->pfiio_size * sizeof(struct pfi_kif); ifstore = mallocarray(io->pfiio_size, sizeof(struct pfi_kif), - M_TEMP, M_WAITOK); + M_TEMP, M_WAITOK | M_ZERO); PF_RULES_RLOCK(); pfi_get_ifaces(io->pfiio_name, ifstore, &io->pfiio_size);