From: Dan Carpenter <dan.carpenter@linaro.org> stable inclusion from stable-v6.6.118 commit 457376c6fbf0c69326a9bf1f72416225f681192b category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/11582 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit e4185bed738da755b191aa3f2e16e8b48450e1b8 upstream. The "req.start" and "req.len" variables are u64 values that come from the user at the start of the function. We mask away the high 32 bits of "req.len" so that's capped at U32_MAX but the "req.start" variable can go up to U64_MAX which means that the addition can still integer overflow. Use check_add_overflow() to fix this bug. Fixes: 095bb6e44eb1 ("mtdchar: add MEMREAD ioctl") Fixes: 6420ac0af95d ("mtdchar: prevent unbounded allocation in MEMWRITE ioctl") Cc: stable@vger.kernel.org Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Cui GaoSheng <cuigaosheng1@huawei.com> --- drivers/mtd/mtdchar.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c index 8dc4f5c493fc..335c702633ff 100644 --- a/drivers/mtd/mtdchar.c +++ b/drivers/mtd/mtdchar.c @@ -599,6 +599,7 @@ mtdchar_write_ioctl(struct mtd_info *mtd, struct mtd_write_req __user *argp) uint8_t *datbuf = NULL, *oobbuf = NULL; size_t datbuf_len, oobbuf_len; int ret = 0; + u64 end; if (copy_from_user(&req, argp, sizeof(req))) return -EFAULT; @@ -618,7 +619,7 @@ mtdchar_write_ioctl(struct mtd_info *mtd, struct mtd_write_req __user *argp) req.len &= 0xffffffff; req.ooblen &= 0xffffffff; - if (req.start + req.len > mtd->size) + if (check_add_overflow(req.start, req.len, &end) || end > mtd->size) return -EINVAL; datbuf_len = min_t(size_t, req.len, mtd->erasesize); @@ -698,6 +699,7 @@ mtdchar_read_ioctl(struct mtd_info *mtd, struct mtd_read_req __user *argp) size_t datbuf_len, oobbuf_len; size_t orig_len, orig_ooblen; int ret = 0; + u64 end; if (copy_from_user(&req, argp, sizeof(req))) return -EFAULT; @@ -724,7 +726,7 @@ mtdchar_read_ioctl(struct mtd_info *mtd, struct mtd_read_req __user *argp) req.len &= 0xffffffff; req.ooblen &= 0xffffffff; - if (req.start + req.len > mtd->size) { + if (check_add_overflow(req.start, req.len, &end) || end > mtd->size) { ret = -EINVAL; goto out; } -- 2.34.1