fs: move fiemap range validation into the file systems instances

Replace fiemap_check_flags with a fiemap_prep helper that also takes the inode and mapped range, and performs the sanity check and truncation previously done in fiemap_check_range. This way the validation is inside the file system itself and thus properly works for the stacked overlayfs case as well.

Christoph Hellwig committed 6 years ago

Commit cddf8a21 parent 273288110 files · +47 −54Browse files

Unified · Split

10 files

Documentation/filesystems/fiemap.txt +7 −5
fs/btrfs/inode.c +1 −1
fs/cifs/smb2ops.c +4 −2
fs/ext4/extents.c +3 −2
fs/f2fs/data.c +2 −1
fs/ioctl.c +24 −39
fs/iomap/fiemap.c +1 −1
fs/nilfs2/inode.c +1 −1
fs/ocfs2/extent_map.c +2 −1
include/linux/fiemap.h +2 −1

Documentation/filesystems/fiemap.txt+7−5

@@ -203,16 +203,18 @@ EINTR once fatal signal received. · 202 unmodified lines
203	203
204	204
205	205	Flag checking should be done at the beginning of the ->fiemap callback via the
206		−fiemap_check_flags() helper:
	206	+fiemap_prep() helper:
207	207
208		−int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags);
	208	+int fiemap_prep(struct inode inode, struct fiemap_extent_info fieinfo,
	209	+ u64 start, u64 *len, u32 supported_flags);
209	210
210	211	The struct fieinfo should be passed in as received from ioctl_fiemap(). The
211	212	set of fiemap flags which the fs understands should be passed via fs_flags. If
212		−fiemap_check_flags finds invalid user flags, it will place the bad values in
	213	+fiemap_prep finds invalid user flags, it will place the bad values in
213	214	fieinfo->fi_flags and return -EBADR. If the file system gets -EBADR, from
214		−fiemap_check_flags(), it should immediately exit, returning that error back to
215		−ioctl_fiemap().
	215	+fiemap_prep(), it should immediately exit, returning that error back to
	216	+ioctl_fiemap(). Additionally the range is validate against the supported
	217	+maximum file size.
216	218
217	219
218	220	For each extent in the request range, the file system should call

fs/btrfs/inode.c+1−1

@@ -8250,7 +8250,7 @@ static int btrfs_fiemap(struct inode inode, struct fiemap_extent_info fieinfo, · 8249 unmodified lines
8250	8250	{
8251	8251	int ret;
8252	8252
8253		− ret = fiemap_check_flags(fieinfo, BTRFS_FIEMAP_FLAGS);
	8253	+ ret = fiemap_prep(inode, fieinfo, start, &len, BTRFS_FIEMAP_FLAGS);
8254	8254	if (ret)
8255	8255	return ret;
8256	8256

fs/cifs/smb2ops.c+4−2

@@ -3408,8 +3408,10 @@ static int smb3_fiemap(struct cifs_tcon *tcon, · 3407 unmodified lines
3408	3408	int i, num, rc, flags, last_blob;
3409	3409	u64 next;
3410	3410
3411		− if (fiemap_check_flags(fei, FIEMAP_FLAG_SYNC))
3412		− return -EBADR;
	3411	+ rc = fiemap_prep(d_inode(cfile->dentry), fei, start, &len,
	3412	+ FIEMAP_FLAG_SYNC);
	3413	+ if (rc)
	3414	+ return rc;
3413	3415
3414	3416	xid = get_xid();
3415	3417	again:

fs/ext4/extents.c+3−2

@@ -4938,8 +4938,9 @@ int ext4_get_es_cache(struct inode inode, struct fiemap_extent_info fieinfo, · 4937 unmodified lines
4938	4938	fieinfo->fi_flags &= ~FIEMAP_FLAG_CACHE;
4939	4939	}
4940	4940
4941		− if (fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC))
4942		− return -EBADR;
	4941	+ error = fiemap_prep(inode, fieinfo, start, &len, FIEMAP_FLAG_SYNC);
	4942	+ if (error)
	4943	+ return error;
4943	4944
4944	4945	error = ext4_fiemap_check_ranges(inode, start, &len);
4945	4946	if (error)

fs/f2fs/data.c+2−1

@@ -1825,7 +1825,8 @@ int f2fs_fiemap(struct inode inode, struct fiemap_extent_info fieinfo, · 1824 unmodified lines
1825	1825	return ret;
1826	1826	}
1827	1827
1828		− ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC \| FIEMAP_FLAG_XATTR);
	1828	+ ret = fiemap_prep(inode, fieinfo, start, &len,
	1829	+ FIEMAP_FLAG_SYNC \| FIEMAP_FLAG_XATTR);
1829	1830	if (ret)
1830	1831	return ret;
1831	1832

fs/ioctl.c+24−39

@@ -149,61 +149,50 @@ int fiemap_fill_next_extent(struct fiemap_extent_info *fieinfo, u64 logical, · 148 unmodified lines
149	149	EXPORT_SYMBOL(fiemap_fill_next_extent);
150	150
151	151	/**
152		− * fiemap_check_flags - check validity of requested flags for fiemap
	152	+ * fiemap_prep - check validity of requested flags for fiemap
	153	+ * @inode: Inode to operate on
153	154	* @fieinfo: Fiemap context passed into ->fiemap
154		− * @fs_flags: Set of fiemap flags that the file system understands
	155	+ * @start: Start of the mapped range
	156	+ * @len: Length of the mapped range, can be truncated by this function.
	157	+ * @supported_flags: Set of fiemap flags that the file system understands
155	158	*
156		− * Called from file system ->fiemap callback. This will compute the
157		− * intersection of valid fiemap flags and those that the fs supports. That
158		− * value is then compared against the user supplied flags. In case of bad user
159		− * flags, the invalid values will be written into the fieinfo structure, and
160		− * -EBADR is returned, which tells ioctl_fiemap() to return those values to
161		− * userspace. For this reason, a return code of -EBADR should be preserved.
	159	+ * This function must be called from each ->fiemap instance to validate the
	160	+ * fiemap request against the file system parameters.
162	161	*
163		− * Returns 0 on success, -EBADR on bad flags.
	162	+ * Returns 0 on success, or a negative error on failure.
164	163	*/
165		−int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags)
	164	+int fiemap_prep(struct inode inode, struct fiemap_extent_info fieinfo,
	165	+ u64 start, u64 *len, u32 supported_flags)
166	166	{
	167	+ u64 maxbytes = inode->i_sb->s_maxbytes;
167	168	u32 incompat_flags;
168	169
169		− incompat_flags = fieinfo->fi_flags & ~(FIEMAP_FLAGS_COMPAT & fs_flags);
170		− if (incompat_flags) {
171		− fieinfo->fi_flags = incompat_flags;
172		− return -EBADR;
173		− }
174		− return 0;
175		−}
176		−EXPORT_SYMBOL(fiemap_check_flags);
177		−
178		−static int fiemap_check_ranges(struct super_block *sb,
179		− u64 start, u64 len, u64 *new_len)
180		−{
181		− u64 maxbytes = (u64) sb->s_maxbytes;
182		−
183		− *new_len = len;
184		−
185		− if (len == 0)
	170	+ if (*len == 0)
186	171	return -EINVAL;
187		−
188	172	if (start > maxbytes)
189	173	return -EFBIG;
190	174
191	175	/*
192	176	* Shrink request scope to what the fs can actually handle.
193	177	*/
194		− if (len > maxbytes \|\| (maxbytes - len) < start)
195		− *new_len = maxbytes - start;
	178	+ if (len > maxbytes \|\| (maxbytes - len) < start)
	179	+ *len = maxbytes - start;
196	180
	181	+ supported_flags &= FIEMAP_FLAGS_COMPAT;
	182	+ incompat_flags = fieinfo->fi_flags & ~supported_flags;
	183	+ if (incompat_flags) {
	184	+ fieinfo->fi_flags = incompat_flags;
	185	+ return -EBADR;
	186	+ }
197	187	return 0;
198	188	}
	189	+EXPORT_SYMBOL(fiemap_prep);
199	190
200	191	static int ioctl_fiemap(struct file filp, struct fiemap __user ufiemap)
201	192	{
202	193	struct fiemap fiemap;
203	194	struct fiemap_extent_info fieinfo = { 0, };
204	195	struct inode *inode = file_inode(filp);
205		− struct super_block *sb = inode->i_sb;
206		− u64 len;
207	196	int error;
208	197
209	198	if (!inode->i_op->fiemap)
@@ -215,11 +204,6 @@ static int ioctl_fiemap(struct file filp, struct fiemap __user ufiemap) · 5 unmodified lines
215	204	if (fiemap.fm_extent_count > FIEMAP_MAX_EXTENTS)
216	205	return -EINVAL;
217	206
218		− error = fiemap_check_ranges(sb, fiemap.fm_start, fiemap.fm_length,
219		− &len);
220		− if (error)
221		− return error;
222		−
223	207	fieinfo.fi_flags = fiemap.fm_flags;
224	208	fieinfo.fi_extents_max = fiemap.fm_extent_count;
225	209	fieinfo.fi_extents_start = ufiemap->fm_extents;
@@ -232,7 +216,8 @@ static int ioctl_fiemap(struct file filp, struct fiemap __user ufiemap) · 6 unmodified lines
232	216	if (fieinfo.fi_flags & FIEMAP_FLAG_SYNC)
233	217	filemap_write_and_wait(inode->i_mapping);
234	218
235		− error = inode->i_op->fiemap(inode, &fieinfo, fiemap.fm_start, len);
	219	+ error = inode->i_op->fiemap(inode, &fieinfo, fiemap.fm_start,
	220	+ fiemap.fm_length);
236	221	fiemap.fm_flags = fieinfo.fi_flags;
237	222	fiemap.fm_mapped_extents = fieinfo.fi_extents_mapped;
238	223	if (copy_to_user(ufiemap, &fiemap, sizeof(fiemap)))
@@ -320,7 +305,7 @@ static int __generic_block_fiemap(struct inode *inode, · 81 unmodified lines
320	305	bool past_eof = false, whole_file = false;
321	306	int ret = 0;
322	307
323		− ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC);
	308	+ ret = fiemap_prep(inode, fieinfo, start, &len, FIEMAP_FLAG_SYNC);
324	309	if (ret)
325	310	return ret;
326	311

fs/iomap/fiemap.c+1−1

@@ -75,7 +75,7 @@ int iomap_fiemap(struct inode inode, struct fiemap_extent_info fi, · 74 unmodified lines
75	75	ctx.fi = fi;
76	76	ctx.prev.type = IOMAP_HOLE;
77	77
78		− ret = fiemap_check_flags(fi, FIEMAP_FLAG_SYNC);
	78	+ ret = fiemap_prep(inode, fi, start, &len, FIEMAP_FLAG_SYNC);
79	79	if (ret)
80	80	return ret;
81	81

fs/nilfs2/inode.c+1−1

@@ -1006,7 +1006,7 @@ int nilfs_fiemap(struct inode inode, struct fiemap_extent_info fieinfo, · 1005 unmodified lines
1006	1006	unsigned int blkbits = inode->i_blkbits;
1007	1007	int ret, n;
1008	1008
1009		− ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC);
	1009	+ ret = fiemap_prep(inode, fieinfo, start, &len, FIEMAP_FLAG_SYNC);
1010	1010	if (ret)
1011	1011	return ret;
1012	1012

fs/ocfs2/extent_map.c+2−1

@@ -746,7 +746,8 @@ int ocfs2_fiemap(struct inode inode, struct fiemap_extent_info fieinfo, · 745 unmodified lines
746	746	struct buffer_head *di_bh = NULL;
747	747	struct ocfs2_extent_rec rec;
748	748
749		− ret = fiemap_check_flags(fieinfo, OCFS2_FIEMAP_FLAGS);
	749	+ ret = fiemap_prep(inode, fieinfo, map_start, &map_len,
	750	+ OCFS2_FIEMAP_FLAGS);
750	751	if (ret)
751	752	return ret;
752	753

include/linux/fiemap.h+2−1

@@ -13,9 +13,10 @@ struct fiemap_extent_info { · 12 unmodified lines
13	13	fiemap_extent array */
14	14	};
15	15
	16	+int fiemap_prep(struct inode inode, struct fiemap_extent_info fieinfo,
	17	+ u64 start, u64 *len, u32 supported_flags);
16	18	int fiemap_fill_next_extent(struct fiemap_extent_info *info, u64 logical,
17	19	u64 phys, u64 len, u32 flags);
18		−int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags);
19	20
20	21	int generic_block_fiemap(struct inode *inode,
21	22	struct fiemap_extent_info *fieinfo, u64 start, u64 len,

fs: move fiemap range validation into the file systems instances

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