From: Greg Kroah-Hartman gregkh@linuxfoundation.org
commit f7e6b19bc76471ba03725fe58e0c218a3d6266c3 upstream.
When doing a "write" ioctl call, properly check that we have permissions to do so before copying anything from userspace or anything else so we can "fail fast". This includes also covering the MEMWRITE ioctl which previously missed checking for this.
Cc: Miquel Raynal miquel.raynal@bootlin.com Cc: Richard Weinberger richard@nod.at Cc: Vignesh Raghavendra vigneshr@ti.com Cc: stable stable@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org [rw: Fixed locking issue] Signed-off-by: Richard Weinberger richard@nod.at Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/mtd/mtdchar.c | 56 +++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 47 insertions(+), 9 deletions(-)
--- a/drivers/mtd/mtdchar.c +++ b/drivers/mtd/mtdchar.c @@ -354,9 +354,6 @@ static int mtdchar_writeoob(struct file uint32_t retlen; int ret = 0;
- if (!(file->f_mode & FMODE_WRITE)) - return -EPERM; - if (length > 4096) return -EINVAL;
@@ -641,6 +638,48 @@ static int mtdchar_ioctl(struct file *fi
pr_debug("MTD_ioctl\n");
+ /* + * Check the file mode to require "dangerous" commands to have write + * permissions. + */ + switch (cmd) { + /* "safe" commands */ + case MEMGETREGIONCOUNT: + case MEMGETREGIONINFO: + case MEMGETINFO: + case MEMREADOOB: + case MEMREADOOB64: + case MEMLOCK: + case MEMUNLOCK: + case MEMISLOCKED: + case MEMGETOOBSEL: + case MEMGETBADBLOCK: + case MEMSETBADBLOCK: + case OTPSELECT: + case OTPGETREGIONCOUNT: + case OTPGETREGIONINFO: + case OTPLOCK: + case ECCGETLAYOUT: + case ECCGETSTATS: + case MTDFILEMODE: + case BLKPG: + case BLKRRPART: + break; + + /* "dangerous" commands */ + case MEMERASE: + case MEMERASE64: + case MEMWRITEOOB: + case MEMWRITEOOB64: + case MEMWRITE: + if (!(file->f_mode & FMODE_WRITE)) + return -EPERM; + break; + + default: + return -ENOTTY; + } + switch (cmd) { case MEMGETREGIONCOUNT: if (copy_to_user(argp, &(mtd->numeraseregions), sizeof(int))) @@ -688,9 +727,6 @@ static int mtdchar_ioctl(struct file *fi { struct erase_info *erase;
- if(!(file->f_mode & FMODE_WRITE)) - return -EPERM; - erase=kzalloc(sizeof(struct erase_info),GFP_KERNEL); if (!erase) ret = -ENOMEM; @@ -983,9 +1019,6 @@ static int mtdchar_ioctl(struct file *fi ret = 0; break; } - - default: - ret = -ENOTTY; }
return ret; @@ -1029,6 +1062,11 @@ static long mtdchar_compat_ioctl(struct struct mtd_oob_buf32 buf; struct mtd_oob_buf32 __user *buf_user = argp;
+ if (!(file->f_mode & FMODE_WRITE)) { + ret = -EPERM; + break; + } + if (copy_from_user(&buf, argp, sizeof(buf))) ret = -EFAULT; else