On 19.02.25 15:18, Sascha Hauer wrote:
> The pattern malloc(size + constant) is dangerous when size can be
> manipulated by an attacker. In that case 'size' can be manipulated
> in a way that 'size + constant' is 0 due to integer overflow. The
> result is a zero sized buffer to which is then data written to.
>
> Avoid this by using size_add() instead.
>
> Reported-by: Jonathan Bar Or <jonathanbaror@xxxxxxxxx>
> Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
Reviewed-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
> ---
> fs/ext4/ext_barebox.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/ext4/ext_barebox.c b/fs/ext4/ext_barebox.c
> index 163c4d2fe1..7480c045d7 100644
> --- a/fs/ext4/ext_barebox.c
> +++ b/fs/ext4/ext_barebox.c
> @@ -189,7 +189,7 @@ static const char *ext_get_link(struct dentry *dentry, struct inode *inode)
>
> BUG_ON(inode->i_link);
>
> - inode->i_link = zalloc(inode->i_size + 1);
> + inode->i_link = zalloc(size_add(inode->i_size, 1));
>
> ret = ext4fs_read_file(node, 0, inode->i_size, inode->i_link);
> if (ret == 0) {
--
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