[PATCH] fs: ubifs: fix bugs involving symlinks in ubifs_findfile

[Heiko Schocher]

Hello Peter,

On 05.05.26 12:38, Peter Collingbourne wrote:
> When encountering a symlink pointing to an absolute path, ubifs_findfile
> would return the target of the symlink as the result instead of resolving
> any following components in the original path. Fix it by following the
> same code path that is used for relative paths except that we set the
> next inode to the root if we see a leading slash.
> 
> The existing code used memcpy and sprintf to copy the symlink target
> into a fixed size stack buffer and was therefore vulnerable to buffer
> overflows with a sufficiently long symlink target. Fix it by using a
> heap buffer for the temporary path during path resolution.
> 
> Signed-off-by: Peter Collingbourne <peter at pcc.me.uk>
> Fixes: 9d7952e4c636 ("ubifs: Add support for looking up directory and relative symlinks")
> ---
>   fs/ubifs/ubifs.c | 70 +++++++++++++++++++++++++++++++-----------------
>   1 file changed, 45 insertions(+), 25 deletions(-)

Thanks!

Reviewed-by: Heiko Schocher <hs at nabladev.com>

bye,
Heiko
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