[PATCH 5.15.y 1/2] gfs2: Improve gfs2_consist_inode() usage

[PATCH 5.15.y 1/2] gfs2: Improve gfs2_consist_inode() usage

[Ruohan Lan]

From: Andrew Price <anprice@redhat.com>

[ Upstream commit 10398ef57aa189153406c110f5957145030f08fe ]

gfs2_consist_inode() logs an error message with the source file and line
number. When we jump before calling it, the line number becomes less
useful as it no longer relates to the source of the error. To aid
troubleshooting, replace the gotos with the gfs2_consist_inode() calls
so that the error messages are more informative.

Signed-off-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Ruohan Lan <ruohanlan@aliyun.com>
---
 fs/gfs2/dir.c   | 31 +++++++++++++++++--------------
 fs/gfs2/glops.c | 34 ++++++++++++++++++++--------------
 fs/gfs2/xattr.c | 28 ++++++++++++++++------------
 3 files changed, 53 insertions(+), 40 deletions(-)

diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
index 42b7dfffb5e7..e1bdc4b0608c 100644
--- a/fs/gfs2/dir.c
+++ b/fs/gfs2/dir.c
@@ -562,15 +562,18 @@ static struct gfs2_dirent *gfs2_dirent_scan(struct inode *inode, void *buf,
 	int ret = 0;
 
 	ret = gfs2_dirent_offset(GFS2_SB(inode), buf);
-	if (ret < 0)
-		goto consist_inode;
-
+	if (ret < 0) {
+		gfs2_consist_inode(GFS2_I(inode));
+		return ERR_PTR(-EIO);
+	}
 	offset = ret;
 	prev = NULL;
 	dent = buf + offset;
 	size = be16_to_cpu(dent->de_rec_len);
-	if (gfs2_check_dirent(GFS2_SB(inode), dent, offset, size, len, 1))
-		goto consist_inode;
+	if (gfs2_check_dirent(GFS2_SB(inode), dent, offset, size, len, 1)) {
+		gfs2_consist_inode(GFS2_I(inode));
+		return ERR_PTR(-EIO);
+	}
 	do {
 		ret = scan(dent, name, opaque);
 		if (ret)
@@ -582,8 +585,10 @@ static struct gfs2_dirent *gfs2_dirent_scan(struct inode *inode, void *buf,
 		dent = buf + offset;
 		size = be16_to_cpu(dent->de_rec_len);
 		if (gfs2_check_dirent(GFS2_SB(inode), dent, offset, size,
-				      len, 0))
-			goto consist_inode;
+				      len, 0)) {
+			gfs2_consist_inode(GFS2_I(inode));
+			return ERR_PTR(-EIO);
+		}
 	} while(1);
 
 	switch(ret) {
@@ -597,10 +602,6 @@ static struct gfs2_dirent *gfs2_dirent_scan(struct inode *inode, void *buf,
 		BUG_ON(ret > 0);
 		return ERR_PTR(ret);
 	}
-
-consist_inode:
-	gfs2_consist_inode(GFS2_I(inode));
-	return ERR_PTR(-EIO);
 }
 
 static int dirent_check_reclen(struct gfs2_inode *dip,
@@ -609,14 +610,16 @@ static int dirent_check_reclen(struct gfs2_inode *dip,
 	const void *ptr = d;
 	u16 rec_len = be16_to_cpu(d->de_rec_len);
 
-	if (unlikely(rec_len < sizeof(struct gfs2_dirent)))
-		goto broken;
+	if (unlikely(rec_len < sizeof(struct gfs2_dirent))) {
+		gfs2_consist_inode(dip);
+		return -EIO;
+	}
 	ptr += rec_len;
 	if (ptr < end_p)
 		return rec_len;
 	if (ptr == end_p)
 		return -ENOENT;
-broken:
+
 	gfs2_consist_inode(dip);
 	return -EIO;
 }
diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
index 5a4b3550d833..fdbae357727b 100644
--- a/fs/gfs2/glops.c
+++ b/fs/gfs2/glops.c
@@ -405,10 +405,14 @@ static int gfs2_dinode_in(struct gfs2_inode *ip, const void *buf)
 	struct inode *inode = &ip->i_inode;
 	bool is_new = inode->i_state & I_NEW;
 
-	if (unlikely(ip->i_no_addr != be64_to_cpu(str->di_num.no_addr)))
-		goto corrupt;
-	if (unlikely(!is_new && inode_wrong_type(inode, mode)))
-		goto corrupt;
+	if (unlikely(ip->i_no_addr != be64_to_cpu(str->di_num.no_addr))) {
+		gfs2_consist_inode(ip);
+		return -EIO;
+	}
+	if (unlikely(!is_new && inode_wrong_type(inode, mode))) {
+		gfs2_consist_inode(ip);
+		return -EIO;
+	}
 	ip->i_no_formal_ino = be64_to_cpu(str->di_num.no_formal_ino);
 	inode->i_mode = mode;
 	if (is_new) {
@@ -444,26 +448,28 @@ static int gfs2_dinode_in(struct gfs2_inode *ip, const void *buf)
 	/* i_diskflags and i_eattr must be set before gfs2_set_inode_flags() */
 	gfs2_set_inode_flags(inode);
 	height = be16_to_cpu(str->di_height);
-	if (unlikely(height > sdp->sd_max_height))
-		goto corrupt;
+	if (unlikely(height > sdp->sd_max_height)) {
+		gfs2_consist_inode(ip);
+		return -EIO;
+	}
 	ip->i_height = (u8)height;
 
 	depth = be16_to_cpu(str->di_depth);
-	if (unlikely(depth > GFS2_DIR_MAX_DEPTH))
-		goto corrupt;
+	if (unlikely(depth > GFS2_DIR_MAX_DEPTH)) {
+		gfs2_consist_inode(ip);
+		return -EIO;
+	}
 	ip->i_depth = (u8)depth;
 	ip->i_entries = be32_to_cpu(str->di_entries);
 
-	if (gfs2_is_stuffed(ip) && inode->i_size > gfs2_max_stuffed_size(ip))
-		goto corrupt;
-
+	if (gfs2_is_stuffed(ip) && inode->i_size > gfs2_max_stuffed_size(ip)) {
+		gfs2_consist_inode(ip);
+		return -EIO;
+	}
 	if (S_ISREG(inode->i_mode))
 		gfs2_set_aops(inode);
 
 	return 0;
-corrupt:
-	gfs2_consist_inode(ip);
-	return -EIO;
 }
 
 /**
diff --git a/fs/gfs2/xattr.c b/fs/gfs2/xattr.c
index 0c5650fe1fd1..2b0fe8cf2173 100644
--- a/fs/gfs2/xattr.c
+++ b/fs/gfs2/xattr.c
@@ -96,30 +96,34 @@ static int ea_foreach_i(struct gfs2_inode *ip, struct buffer_head *bh,
 		return -EIO;
 
 	for (ea = GFS2_EA_BH2FIRST(bh);; prev = ea, ea = GFS2_EA2NEXT(ea)) {
-		if (!GFS2_EA_REC_LEN(ea))
-			goto fail;
+		if (!GFS2_EA_REC_LEN(ea)) {
+			gfs2_consist_inode(ip);
+			return -EIO;
+		}
 		if (!(bh->b_data <= (char *)ea && (char *)GFS2_EA2NEXT(ea) <=
-						  bh->b_data + bh->b_size))
-			goto fail;
-		if (!gfs2_eatype_valid(sdp, ea->ea_type))
-			goto fail;
+						  bh->b_data + bh->b_size)) {
+			gfs2_consist_inode(ip);
+			return -EIO;
+		}
+		if (!gfs2_eatype_valid(sdp, ea->ea_type)) {
+			gfs2_consist_inode(ip);
+			return -EIO;
+		}
 		error = ea_call(ip, bh, ea, prev, data);
 		if (error)
 			return error;
 
 		if (GFS2_EA_IS_LAST(ea)) {
 			if ((char *)GFS2_EA2NEXT(ea) !=
-			    bh->b_data + bh->b_size)
-				goto fail;
+			    bh->b_data + bh->b_size) {
+				gfs2_consist_inode(ip);
+				return -EIO;
+			}
 			break;
 		}
 	}
 
 	return error;
-
-fail:
-	gfs2_consist_inode(ip);
-	return -EIO;
 }
 
 static int ea_foreach(struct gfs2_inode *ip, ea_call_t ea_call, void *data)
-- 
2.43.0

[PATCH 5.15.y 2/2] gfs2: Validate i_depth for exhash directories

[Ruohan Lan]

From: Andrew Price <anprice@redhat.com>

[ Upstream commit 557c024ca7250bb65ae60f16c02074106c2f197b ]

A fuzzer test introduced corruption that ends up with a depth of 0 in
dir_e_read(), causing an undefined shift by 32 at:

  index = hash >> (32 - dip->i_depth);

As calculated in an open-coded way in dir_make_exhash(), the minimum
depth for an exhash directory is ilog2(sdp->sd_hash_ptrs) and 0 is
invalid as sdp->sd_hash_ptrs is fixed as sdp->bsize / 16 at mount time.

So we can avoid the undefined behaviour by checking for depth values
lower than the minimum in gfs2_dinode_in(). Values greater than the
maximum are already being checked for there.

Also switch the calculation in dir_make_exhash() to use ilog2() to
clarify how the depth is calculated.

Tested with the syzkaller repro.c and xfstests '-g quick'.

Reported-by: syzbot+4708579bb230a0582a57@syzkaller.appspotmail.com
Signed-off-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Ruohan Lan <ruohanlan@aliyun.com>
---
 fs/gfs2/dir.c   | 6 ++----
 fs/gfs2/glops.c | 6 ++++++
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
index e1bdc4b0608c..559cad553db6 100644
--- a/fs/gfs2/dir.c
+++ b/fs/gfs2/dir.c
@@ -60,6 +60,7 @@
 #include <linux/crc32.h>
 #include <linux/vmalloc.h>
 #include <linux/bio.h>
+#include <linux/log2.h>
 
 #include "gfs2.h"
 #include "incore.h"
@@ -912,7 +913,6 @@ static int dir_make_exhash(struct inode *inode)
 	struct qstr args;
 	struct buffer_head *bh, *dibh;
 	struct gfs2_leaf *leaf;
-	int y;
 	u32 x;
 	__be64 *lp;
 	u64 bn;
@@ -979,9 +979,7 @@ static int dir_make_exhash(struct inode *inode)
 	i_size_write(inode, sdp->sd_sb.sb_bsize / 2);
 	gfs2_add_inode_blocks(&dip->i_inode, 1);
 	dip->i_diskflags |= GFS2_DIF_EXHASH;
-
-	for (x = sdp->sd_hash_ptrs, y = -1; x; x >>= 1, y++) ;
-	dip->i_depth = y;
+	dip->i_depth = ilog2(sdp->sd_hash_ptrs);
 
 	gfs2_dinode_out(dip, dibh->b_data);
 
diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
index fdbae357727b..8a077de9ee0a 100644
--- a/fs/gfs2/glops.c
+++ b/fs/gfs2/glops.c
@@ -11,6 +11,7 @@
 #include <linux/bio.h>
 #include <linux/posix_acl.h>
 #include <linux/security.h>
+#include <linux/log2.h>
 
 #include "gfs2.h"
 #include "incore.h"
@@ -459,6 +460,11 @@ static int gfs2_dinode_in(struct gfs2_inode *ip, const void *buf)
 		gfs2_consist_inode(ip);
 		return -EIO;
 	}
+	if ((ip->i_diskflags & GFS2_DIF_EXHASH) &&
+	    depth < ilog2(sdp->sd_hash_ptrs)) {
+		gfs2_consist_inode(ip);
+		return -EIO;
+	}
 	ip->i_depth = (u8)depth;
 	ip->i_entries = be32_to_cpu(str->di_entries);
 
-- 
2.43.0