Re: [PATCH] src/attr_replace_test: limit size of extended attribute value

Darrick J. Wong
2019-05-20T16:23:50Z

On Fri, May 17, 2019 at 01:06:53PM +0100, Luis Henriques wrote:
> The maximum size for extended attribute values is 65536 (XATTR_SIZE_MAX).
> Since there are filesystems that can set blksize to really big values
> (CephFS for example has a default of 4M), it's easy to have this test
> failing with fsetxattr returning -E2BIG.
>
> Cc: Darrick J. Wong <darrick.wong@oracle.com>
> Signed-off-by: Luis Henriques <lhenriques@suse.com>
> ---
> src/attr_replace_test.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/src/attr_replace_test.c b/src/attr_replace_test.c
> index 0720bfdc18ab..1ca9bf11ba58 100644
> --- a/src/attr_replace_test.c
> +++ b/src/attr_replace_test.c
> @@ -9,6 +9,7 @@
> #include <sys/types.h>
> #include <sys/xattr.h>
> #include <sys/stat.h>
> +#include <linux/limits.h>
>
> #define die() do { perror(""); \
> fprintf(stderr, "error at line %d\n", __LINE__); \
> @@ -44,6 +45,8 @@ int main(int argc, char *argv[])
> size = sbuf.st_blksize * 3 / 4;
> if (!size)
> fail("Invalid st_blksize(%ld)\n", sbuf.st_blksize);
> + if (size > XATTR_SIZE_MAX)
> + size = XATTR_SIZE_MAX;

Looks good to me (this or the min()/MIN()/whatever version),

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> value = malloc(size);
> if (!value)
> fail("Failed to allocate memory\n");