From 9cf89ade1afd450a5ff25ee65acbebb94b011287 Mon Sep 17 00:00:00 2001 From: Vincent Pelletier Date: Wed, 18 Jan 2017 00:57:44 +0000 Subject: [PATCH] usb: gadget: f_fs: Assorted buffer overflow checks. commit 83e526f2a2fa4b2e82b6bd3ddbb26b70acfa8947 upstream. OS descriptor head, when flagged as provided, is accessed without checking if it fits in provided buffer. Verify length before access. Also, there are other places where buffer length it checked after accessing offsets which are potentially past the end. Check buffer length before as well to fail cleanly. Signed-off-by: Vincent Pelletier Acked-by: Felipe Balbi Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_fs.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index 803c503a2e3d..cfda1a1c0ab6 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -2079,6 +2079,8 @@ static int __ffs_data_do_os_desc(enum ffs_os_desc_type type, if (len < sizeof(*d) || h->interface >= ffs->interfaces_count) return -EINVAL; length = le32_to_cpu(d->dwSize); + if (len < length) + return -EINVAL; type = le32_to_cpu(d->dwPropertyDataType); if (type < USB_EXT_PROP_UNICODE || type > USB_EXT_PROP_UNICODE_MULTI) { @@ -2087,6 +2089,11 @@ static int __ffs_data_do_os_desc(enum ffs_os_desc_type type, return -EINVAL; } pnl = le16_to_cpu(d->wPropertyNameLength); + if (length < 14 + pnl) { + pr_vdebug("invalid os descriptor length: %d pnl:%d (descriptor %d)\n", + length, pnl, type); + return -EINVAL; + } pdl = le32_to_cpu(*(u32 *)((u8 *)data + 10 + pnl)); if (length != 14 + pnl + pdl) { pr_vdebug("invalid os descriptor length: %d pnl:%d pdl:%d (descriptor %d)\n", @@ -2171,6 +2178,9 @@ static int __ffs_data_got_descs(struct ffs_data *ffs, } } if (flags & (1 << i)) { + if (len < 4) { + goto error; + } os_descs_count = get_unaligned_le32(data); data += 4; len -= 4; @@ -2243,7 +2253,8 @@ static int __ffs_data_got_strings(struct ffs_data *ffs, ENTER(); - if (unlikely(get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC || + if (unlikely(len < 16 || + get_unaligned_le32(data) != FUNCTIONFS_STRINGS_MAGIC || get_unaligned_le32(data + 4) != len)) goto error; str_count = get_unaligned_le32(data + 8); -- 2.34.1