6.6-stable review patch. If anyone has any objections, please let me know.
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From: Ivan Avdeev me@provod.works
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 me@provod.works Link: https://lore.kernel.org/r/20240413150124.1062026-1-me@provod.works Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/gadget/function/uvc_configfs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- 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(cons
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; }