6.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Johannes Berg johannes.berg@intel.com
commit 267ed02c2121b75e0eaaa338240453b576039e4a upstream.
dev_t is a kernel type and may have different definitions in kernel and userspace. On 32-bit x86 this currently makes the stat structure being 4 bytes longer in the user code, causing stack corruption.
However, this is (potentially) not the only problem, since dev_t is a different type on user/kernel side, so we don't know that the major/minor encoding isn't also different. Decode/encode it instead to address both problems.
Cc: stable@vger.kernel.org Fixes: 74ce793bcbde ("hostfs: Fix ephemeral inodes") Link: https://patch.msgid.link/20240702092440.acc960585dd5.Id0767e12f562a69c6cd3c3... Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/hostfs/hostfs.h | 7 ++++--- fs/hostfs/hostfs_kern.c | 10 ++++++---- fs/hostfs/hostfs_user.c | 7 ++++--- 3 files changed, 14 insertions(+), 10 deletions(-)
--- a/fs/hostfs/hostfs.h +++ b/fs/hostfs/hostfs.h @@ -63,9 +63,10 @@ struct hostfs_stat { struct hostfs_timespec atime, mtime, ctime; unsigned int blksize; unsigned long long blocks; - unsigned int maj; - unsigned int min; - dev_t dev; + struct { + unsigned int maj; + unsigned int min; + } rdev, dev; };
extern int stat_file(const char *path, struct hostfs_stat *p, int fd); --- a/fs/hostfs/hostfs_kern.c +++ b/fs/hostfs/hostfs_kern.c @@ -530,10 +530,11 @@ static int hostfs_inode_update(struct in static int hostfs_inode_set(struct inode *ino, void *data) { struct hostfs_stat *st = data; - dev_t rdev; + dev_t dev, rdev;
/* Reencode maj and min with the kernel encoding.*/ - rdev = MKDEV(st->maj, st->min); + rdev = MKDEV(st->rdev.maj, st->rdev.min); + dev = MKDEV(st->dev.maj, st->dev.min);
switch (st->mode & S_IFMT) { case S_IFLNK: @@ -559,7 +560,7 @@ static int hostfs_inode_set(struct inode return -EIO; }
- HOSTFS_I(ino)->dev = st->dev; + HOSTFS_I(ino)->dev = dev; ino->i_ino = st->ino; ino->i_mode = st->mode; return hostfs_inode_update(ino, st); @@ -568,8 +569,9 @@ static int hostfs_inode_set(struct inode static int hostfs_inode_test(struct inode *inode, void *data) { const struct hostfs_stat *st = data; + dev_t dev = MKDEV(st->dev.maj, st->dev.min);
- return inode->i_ino == st->ino && HOSTFS_I(inode)->dev == st->dev; + return inode->i_ino == st->ino && HOSTFS_I(inode)->dev == dev; }
static struct inode *hostfs_iget(struct super_block *sb, char *name) --- a/fs/hostfs/hostfs_user.c +++ b/fs/hostfs/hostfs_user.c @@ -34,9 +34,10 @@ static void stat64_to_hostfs(const struc p->mtime.tv_nsec = 0; p->blksize = buf->st_blksize; p->blocks = buf->st_blocks; - p->maj = os_major(buf->st_rdev); - p->min = os_minor(buf->st_rdev); - p->dev = buf->st_dev; + p->rdev.maj = os_major(buf->st_rdev); + p->rdev.min = os_minor(buf->st_rdev); + p->dev.maj = os_major(buf->st_dev); + p->dev.min = os_minor(buf->st_dev); }
int stat_file(const char *path, struct hostfs_stat *p, int fd)