From 7a54e5052bde582fd0e7677334fe7a5be92e242c Mon Sep 17 00:00:00 2001 From: Ivan Avdeev Date: Sat, 13 Apr 2024 11:01:24 -0400 Subject: [PATCH] usb: gadget: uvc: use correct buffer size when parsing configfs lists commit 650ae71c80749fc7cb8858c8049f532eaec64410 upstream. This commit fixes uvc gadget support on 32-bit platforms. Commit 0df28607c5cb ("usb: gadget: uvc: Generalise helper functions for reuse") introduced a helper function __uvcg_iter_item_entries() to aid with parsing lists of items on configfs attributes stores. This function is a generalization of another very similar function, which used a stack-allocated temporary buffer of fixed size for each item in the list and used the sizeof() operator to check for potential buffer overruns. The new function was changed to allocate the now variably sized temp buffer on heap, but wasn't properly updated to also check for max buffer size using the computed size instead of sizeof() operator. As a result, the maximum item size was 7 (plus null terminator) on 64-bit platforms, and 3 on 32-bit ones. While 7 is accidentally just barely enough, 3 is definitely too small for some of UVC configfs attributes. For example, dwFrameInteval, specified in 100ns units, usually has 6-digit item values, e.g. 166666 for 60fps. Cc: stable@vger.kernel.org Fixes: 0df28607c5cb ("usb: gadget: uvc: Generalise helper functions for reuse") Signed-off-by: Ivan Avdeev Link: https://lore.kernel.org/r/20240413150124.1062026-1-me@provod.works Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/uvc_configfs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/usb/gadget/function/uvc_configfs.c b/drivers/usb/gadget/function/uvc_configfs.c index 9bf0e985acfa..d16c04d2961b 100644 --- a/drivers/usb/gadget/function/uvc_configfs.c +++ b/drivers/usb/gadget/function/uvc_configfs.c @@ -92,10 +92,10 @@ static int __uvcg_iter_item_entries(const char *page, size_t len, while (pg - page < len) { i = 0; - while (i < sizeof(buf) && (pg - page < len) && + while (i < bufsize && (pg - page < len) && *pg != '\0' && *pg != '\n') buf[i++] = *pg++; - if (i == sizeof(buf)) { + if (i == bufsize) { ret = -EINVAL; goto out_free_buf; }