This is a note to let you know that I've just added the patch titled
usb: gadget: f_uac2: Replace snprintf() with the safer scnprintf() variant
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-gadget-f_uac2-replace-snprintf-with-the-safer-sc.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit d4614c7cd1eb5e09e25fc61b47d17b6701c98b51
Author: Lee Jones <lee@xxxxxxxxxx>
Date: Wed Dec 13 16:42:32 2023 +0000
usb: gadget: f_uac2: Replace snprintf() with the safer scnprintf() variant
[ Upstream commit 60034e0aedf507888c4a880f57011bb7f5d7700c ]
There is a general misunderstanding amongst engineers that {v}snprintf()
returns the length of the data *actually* encoded into the destination
array. However, as per the C99 standard {v}snprintf() really returns
the length of the data that *would have been* written if there were
enough space for it. This misunderstanding has led to buffer-overruns
in the past. It's generally considered safer to use the {v}scnprintf()
variants in their place (or even sprintf() in simple cases). So let's
do that.
Link: https://lwn.net/Articles/69419/
Link: https://github.com/KSPP/linux/issues/105
Cc: James Gruber <jimmyjgruber@xxxxxxxxx>
Cc: Yadwinder Singh <yadi.brar01@xxxxxxxxx>
Cc: Jaswinder Singh <jaswinder.singh@xxxxxxxxxx>
Cc: Ruslan Bilovol <ruslan.bilovol@xxxxxxxxx>
Signed-off-by: Lee Jones <lee@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20231213164246.1021885-4-lee@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Stable-dep-of: 9499327714de ("usb: gadget: f_uac2: fix return value for UAC2_ATTRIBUTE_STRING store")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/usb/gadget/function/f_uac2.c b/drivers/usb/gadget/function/f_uac2.c
index 0219cd79493a7..55a4f07bc9cc1 100644
--- a/drivers/usb/gadget/function/f_uac2.c
+++ b/drivers/usb/gadget/function/f_uac2.c
@@ -2042,7 +2042,7 @@ static ssize_t f_uac2_opts_##name##_show(struct config_item *item, \
int result; \
\
mutex_lock(&opts->lock); \
- result = snprintf(page, sizeof(opts->name), "%s", opts->name); \
+ result = scnprintf(page, sizeof(opts->name), "%s", opts->name); \
mutex_unlock(&opts->lock); \
\
return result; \
@@ -2060,7 +2060,7 @@ static ssize_t f_uac2_opts_##name##_store(struct config_item *item, \
goto end; \
} \
\
- ret = snprintf(opts->name, min(sizeof(opts->name), len), \
+ ret = scnprintf(opts->name, min(sizeof(opts->name), len), \
"%s", page); \
\
end: \
@@ -2178,7 +2178,7 @@ static struct usb_function_instance *afunc_alloc_inst(void)
opts->req_number = UAC2_DEF_REQ_NUM;
opts->fb_max = FBACK_FAST_MAX;
- snprintf(opts->function_name, sizeof(opts->function_name), "Source/Sink");
+ scnprintf(opts->function_name, sizeof(opts->function_name), "Source/Sink");
return &opts->func_inst;
}
