From 0e539ca1bbbe85a86549c97a30a765ada4a09df9 Mon Sep 17 00:00:00 2001 From: Andrew Price Date: Wed, 7 Oct 2020 12:30:58 +0100 Subject: [PATCH] gfs2: Fix NULL pointer dereference in gfs2_rgrp_dump When an rindex entry is found to be corrupt, compute_bitstructs() calls gfs2_consist_rgrpd() which calls gfs2_rgrp_dump() like this: gfs2_rgrp_dump(NULL, rgd->rd_gl, fs_id_buf); gfs2_rgrp_dump then dereferences the gl without checking it and we get BUG: KASAN: null-ptr-deref in gfs2_rgrp_dump+0x28/0x280 because there's no rgrp glock involved while reading the rindex on mount. Fix this by changing gfs2_rgrp_dump to take an rgrp argument. Reported-by: syzbot+43fa87986bdd31df9de6@syzkaller.appspotmail.com Signed-off-by: Andrew Price Signed-off-by: Andreas Gruenbacher --- fs/gfs2/glops.c | 11 ++++++++++- fs/gfs2/rgrp.c | 9 +++------ fs/gfs2/rgrp.h | 2 +- fs/gfs2/util.c | 2 +- 4 files changed, 15 insertions(+), 9 deletions(-) diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c index de1d5f1d9ff8..c2c90747d79b 100644 --- a/fs/gfs2/glops.c +++ b/fs/gfs2/glops.c @@ -227,6 +227,15 @@ static void rgrp_go_inval(struct gfs2_glock *gl, int flags) rgd->rd_flags &= ~GFS2_RDF_UPTODATE; } +static void gfs2_rgrp_go_dump(struct seq_file *seq, struct gfs2_glock *gl, + const char *fs_id_buf) +{ + struct gfs2_rgrpd *rgd = gfs2_glock2rgrp(gl); + + if (rgd) + gfs2_rgrp_dump(seq, rgd, fs_id_buf); +} + static struct gfs2_inode *gfs2_glock2inode(struct gfs2_glock *gl) { struct gfs2_inode *ip; @@ -712,7 +721,7 @@ const struct gfs2_glock_operations gfs2_rgrp_glops = { .go_sync = rgrp_go_sync, .go_inval = rgrp_go_inval, .go_lock = gfs2_rgrp_go_lock, - .go_dump = gfs2_rgrp_dump, + .go_dump = gfs2_rgrp_go_dump, .go_type = LM_TYPE_RGRP, .go_flags = GLOF_LVB, }; diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c index 074f228ea839..1bba5a9d45fa 100644 --- a/fs/gfs2/rgrp.c +++ b/fs/gfs2/rgrp.c @@ -2209,20 +2209,17 @@ static void rgblk_free(struct gfs2_sbd *sdp, struct gfs2_rgrpd *rgd, /** * gfs2_rgrp_dump - print out an rgrp * @seq: The iterator - * @gl: The glock in question + * @rgd: The rgrp in question * @fs_id_buf: pointer to file system id (if requested) * */ -void gfs2_rgrp_dump(struct seq_file *seq, struct gfs2_glock *gl, +void gfs2_rgrp_dump(struct seq_file *seq, struct gfs2_rgrpd *rgd, const char *fs_id_buf) { - struct gfs2_rgrpd *rgd = gl->gl_object; struct gfs2_blkreserv *trs; const struct rb_node *n; - if (rgd == NULL) - return; gfs2_print_dbg(seq, "%s R: n:%llu f:%02x b:%u/%u i:%u r:%u e:%u\n", fs_id_buf, (unsigned long long)rgd->rd_addr, rgd->rd_flags, @@ -2253,7 +2250,7 @@ static void gfs2_rgrp_error(struct gfs2_rgrpd *rgd) (unsigned long long)rgd->rd_addr); fs_warn(sdp, "umount on all nodes and run fsck.gfs2 to fix the error\n"); sprintf(fs_id_buf, "fsid=%s: ", sdp->sd_fsname); - gfs2_rgrp_dump(NULL, rgd->rd_gl, fs_id_buf); + gfs2_rgrp_dump(NULL, rgd, fs_id_buf); rgd->rd_flags |= GFS2_RDF_ERROR; } diff --git a/fs/gfs2/rgrp.h b/fs/gfs2/rgrp.h index a1d7e14fc55b..9a587ada51ed 100644 --- a/fs/gfs2/rgrp.h +++ b/fs/gfs2/rgrp.h @@ -67,7 +67,7 @@ extern void gfs2_rlist_add(struct gfs2_inode *ip, struct gfs2_rgrp_list *rlist, extern void gfs2_rlist_alloc(struct gfs2_rgrp_list *rlist); extern void gfs2_rlist_free(struct gfs2_rgrp_list *rlist); extern u64 gfs2_ri_total(struct gfs2_sbd *sdp); -extern void gfs2_rgrp_dump(struct seq_file *seq, struct gfs2_glock *gl, +extern void gfs2_rgrp_dump(struct seq_file *seq, struct gfs2_rgrpd *rgd, const char *fs_id_buf); extern int gfs2_rgrp_send_discards(struct gfs2_sbd *sdp, u64 offset, struct buffer_head *bh, diff --git a/fs/gfs2/util.c b/fs/gfs2/util.c index 1cd0328cae20..0fba3bf64189 100644 --- a/fs/gfs2/util.c +++ b/fs/gfs2/util.c @@ -419,7 +419,7 @@ void gfs2_consist_rgrpd_i(struct gfs2_rgrpd *rgd, char fs_id_buf[sizeof(sdp->sd_fsname) + 7]; sprintf(fs_id_buf, "fsid=%s: ", sdp->sd_fsname); - gfs2_rgrp_dump(NULL, rgd->rd_gl, fs_id_buf); + gfs2_rgrp_dump(NULL, rgd, fs_id_buf); gfs2_lm(sdp, "fatal: filesystem consistency error\n" " RG = %llu\n"