On Tue, Oct 29, 2024 at 1:06 PM Marc Dionne <marc.c.dionne@xxxxxxxxx> wrote:
>
> From: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
>
> The number of slabs can easily exceed the hard coded MAX_SLABS in the
> slabinfo tool, causing it to overwrite memory and crash.
>
> Increase the value of MAX_SLABS, and check if that has been exceeded for
> each new slab, instead of at the end when it's already too late. Also
> move the check for MAX_ALIASES into the loop body.
>
> Signed-off-by: Marc Dionne <marc.dionne@xxxxxxxxxxxx>
> ---
> tools/mm/slabinfo.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/tools/mm/slabinfo.c b/tools/mm/slabinfo.c
> index cfaeaea71042..2c9c86d677ed 100644
> --- a/tools/mm/slabinfo.c
> +++ b/tools/mm/slabinfo.c
> @@ -21,7 +21,7 @@
> #include <regex.h>
> #include <errno.h>
>
> -#define MAX_SLABS 500
> +#define MAX_SLABS 1000
> #define MAX_ALIASES 500
> #define MAX_NODES 1024
>
> @@ -1240,6 +1240,8 @@ static void read_slab_dir(void)
> p--;
> alias->ref = strdup(p);
> alias++;
> + if (aliases > MAX_ALIASES)
This is not quite right, needs to be alias - aliasinfo. Will send a V2.
> + fatal("Too many aliases\n");
> break;
> case DT_DIR:
> if (chdir(de->d_name))
> @@ -1301,6 +1303,8 @@ static void read_slab_dir(void)
> if (slab->name[0] == ':')
> alias_targets++;
> slab++;
> + if (slab - slabinfo > MAX_SLABS)
> + fatal("Too many slabs\n");
> break;
> default :
> fatal("Unknown file type %lx\n", de->d_type);
> @@ -1310,10 +1314,6 @@ static void read_slab_dir(void)
> slabs = slab - slabinfo;
> actual_slabs = slabs;
> aliases = alias - aliasinfo;
> - if (slabs > MAX_SLABS)
> - fatal("Too many slabs\n");
> - if (aliases > MAX_ALIASES)
> - fatal("Too many aliases\n");
> }
>
> static void output_slabs(void)
> --
> 2.47.0
>
