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authorAmir Goldstein <amir73il@gmail.com>2023-11-22 15:27:02 +0300
committerChristian Brauner <brauner@kernel.org>2023-11-24 11:22:28 +0300
commitfeebea75bdf499aefd11d0df7b02d384a9f92fc1 (patch)
tree37614e8252ee18bc4931d95e8ed8491fdf7e292a /fs/splice.c
parent2a33e2ddc6ebf9b5468091aded8a38f57de9a580 (diff)
downloadlinux-feebea75bdf499aefd11d0df7b02d384a9f92fc1.tar.xz
splice: move permission hook out of splice_direct_to_actor()
vfs_splice_read() has a permission hook inside rw_verify_area() and it is called from do_splice_direct() -> splice_direct_to_actor(). The callers of do_splice_direct() (e.g. vfs_copy_file_range()) already call rw_verify_area() for the entire range, but the other caller of splice_direct_to_actor() (nfsd) does not. Add the rw_verify_area() checks in nfsd_splice_read() and use a variant of vfs_splice_read() without rw_verify_area() check in splice_direct_to_actor() to avoid the redundant rw_verify_area() checks. This is needed for fanotify "pre content" events. Acked-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20231122122715.2561213-4-amir73il@gmail.com Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'fs/splice.c')
-rw-r--r--fs/splice.c58
1 files changed, 35 insertions, 23 deletions
diff --git a/fs/splice.c b/fs/splice.c
index 6e917db6f49a..6fc2c27e9520 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -944,27 +944,15 @@ static void do_splice_eof(struct splice_desc *sd)
sd->splice_eof(sd);
}
-/**
- * vfs_splice_read - Read data from a file and splice it into a pipe
- * @in: File to splice from
- * @ppos: Input file offset
- * @pipe: Pipe to splice to
- * @len: Number of bytes to splice
- * @flags: Splice modifier flags (SPLICE_F_*)
- *
- * Splice the requested amount of data from the input file to the pipe. This
- * is synchronous as the caller must hold the pipe lock across the entire
- * operation.
- *
- * If successful, it returns the amount of data spliced, 0 if it hit the EOF or
- * a hole and a negative error code otherwise.
+/*
+ * Callers already called rw_verify_area() on the entire range.
+ * No need to call it for sub ranges.
*/
-long vfs_splice_read(struct file *in, loff_t *ppos,
- struct pipe_inode_info *pipe, size_t len,
- unsigned int flags)
+static long do_splice_read(struct file *in, loff_t *ppos,
+ struct pipe_inode_info *pipe, size_t len,
+ unsigned int flags)
{
unsigned int p_space;
- int ret;
if (unlikely(!(in->f_mode & FMODE_READ)))
return -EBADF;
@@ -975,10 +963,6 @@ long vfs_splice_read(struct file *in, loff_t *ppos,
p_space = pipe->max_usage - pipe_occupancy(pipe->head, pipe->tail);
len = min_t(size_t, len, p_space << PAGE_SHIFT);
- ret = rw_verify_area(READ, in, ppos, len);
- if (unlikely(ret < 0))
- return ret;
-
if (unlikely(len > MAX_RW_COUNT))
len = MAX_RW_COUNT;
@@ -992,6 +976,34 @@ long vfs_splice_read(struct file *in, loff_t *ppos,
return copy_splice_read(in, ppos, pipe, len, flags);
return in->f_op->splice_read(in, ppos, pipe, len, flags);
}
+
+/**
+ * vfs_splice_read - Read data from a file and splice it into a pipe
+ * @in: File to splice from
+ * @ppos: Input file offset
+ * @pipe: Pipe to splice to
+ * @len: Number of bytes to splice
+ * @flags: Splice modifier flags (SPLICE_F_*)
+ *
+ * Splice the requested amount of data from the input file to the pipe. This
+ * is synchronous as the caller must hold the pipe lock across the entire
+ * operation.
+ *
+ * If successful, it returns the amount of data spliced, 0 if it hit the EOF or
+ * a hole and a negative error code otherwise.
+ */
+long vfs_splice_read(struct file *in, loff_t *ppos,
+ struct pipe_inode_info *pipe, size_t len,
+ unsigned int flags)
+{
+ int ret;
+
+ ret = rw_verify_area(READ, in, ppos, len);
+ if (unlikely(ret < 0))
+ return ret;
+
+ return do_splice_read(in, ppos, pipe, len, flags);
+}
EXPORT_SYMBOL_GPL(vfs_splice_read);
/**
@@ -1066,7 +1078,7 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
size_t read_len;
loff_t pos = sd->pos, prev_pos = pos;
- ret = vfs_splice_read(in, &pos, pipe, len, flags);
+ ret = do_splice_read(in, &pos, pipe, len, flags);
if (unlikely(ret <= 0))
goto read_failure;