Re: [PATCH 5.15.y] exfat: check if filename entries exceeds max filename length

[Greg KH]

On Sat, Aug 19, 2023 at 12:53:37AM -0700, Harshit Mogalapalli wrote:
> From: Namjae Jeon <linkinjeon@xxxxxxxxxx>
> 
> [ Upstream commit d42334578eba1390859012ebb91e1e556d51db49 ]
> 
> exfat_extract_uni_name copies characters from a given file name entry into
> the 'uniname' variable. This variable is actually defined on the stack of
> the exfat_readdir() function. According to the definition of
> the 'exfat_uni_name' type, the file name should be limited 255 characters
> (+ null teminator space), but the exfat_get_uniname_from_ext_entry()
> function can write more characters because there is no check if filename
> entries exceeds max filename length. This patch add the check not to copy
> filename characters when exceeding max filename length.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Cc: Yuezhang Mo <Yuezhang.Mo@xxxxxxxx>
> Reported-by: Maxim Suhanov <dfirblog@xxxxxxxxx>
> Reviewed-by: Sungjong Seo <sj1557.seo@xxxxxxxxxxx>
> Signed-off-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> [Harshit: backport to 5.15.y]
> Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx>
> ---
> The conflict resolved patch for 6.1.y applies cleanly to 5.15.y as
> well.
> Note: This fix is already present in 5.10.y but missing in 5.15.y

Thanks for catching this, now queued up.

greg k-h