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| author | Florian Lehner <dev@der-flo.net> | 2022-10-28 20:34:05 +0200 |
|---|---|---|
| committer | Martin KaFai Lau <martin.lau@kernel.org> | 2022-10-28 15:45:58 -0700 |
| commit | e39e739ab57399f46167d453bbdb8ef8d57c6488 (patch) | |
| tree | 4c71035f5de99b1d0d4d921ecb00775beda8add4 /kernel/bpf/cpumap.c | |
| parent | b6d207999c350b19a787e48757f98198d0bf3e5b (diff) | |
| download | linux-stable-e39e739ab57399f46167d453bbdb8ef8d57c6488.tar.gz linux-stable-e39e739ab57399f46167d453bbdb8ef8d57c6488.tar.bz2 linux-stable-e39e739ab57399f46167d453bbdb8ef8d57c6488.zip | |
bpf: check max_entries before allocating memory
For maps of type BPF_MAP_TYPE_CPUMAP memory is allocated first before
checking the max_entries argument. If then max_entries is greater than
NR_CPUS additional work needs to be done to free allocated memory before
an error is returned.
This changes moves the check on max_entries before the allocation
happens.
Signed-off-by: Florian Lehner <dev@der-flo.net>
Link: https://lore.kernel.org/r/20221028183405.59554-1-dev@der-flo.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Diffstat (limited to 'kernel/bpf/cpumap.c')
| -rw-r--r-- | kernel/bpf/cpumap.c | 20 |
1 files changed, 8 insertions, 12 deletions
diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c index b5ba34ddd4b6..bb03fdba73bb 100644 --- a/kernel/bpf/cpumap.c +++ b/kernel/bpf/cpumap.c @@ -85,7 +85,6 @@ static struct bpf_map *cpu_map_alloc(union bpf_attr *attr) { u32 value_size = attr->value_size; struct bpf_cpu_map *cmap; - int err = -ENOMEM; if (!bpf_capable()) return ERR_PTR(-EPERM); @@ -97,29 +96,26 @@ static struct bpf_map *cpu_map_alloc(union bpf_attr *attr) attr->map_flags & ~BPF_F_NUMA_NODE) return ERR_PTR(-EINVAL); + /* Pre-limit array size based on NR_CPUS, not final CPU check */ + if (attr->max_entries > NR_CPUS) + return ERR_PTR(-E2BIG); + cmap = bpf_map_area_alloc(sizeof(*cmap), NUMA_NO_NODE); if (!cmap) return ERR_PTR(-ENOMEM); bpf_map_init_from_attr(&cmap->map, attr); - /* Pre-limit array size based on NR_CPUS, not final CPU check */ - if (cmap->map.max_entries > NR_CPUS) { - err = -E2BIG; - goto free_cmap; - } - /* Alloc array for possible remote "destination" CPUs */ cmap->cpu_map = bpf_map_area_alloc(cmap->map.max_entries * sizeof(struct bpf_cpu_map_entry *), cmap->map.numa_node); - if (!cmap->cpu_map) - goto free_cmap; + if (!cmap->cpu_map) { + bpf_map_area_free(cmap); + return ERR_PTR(-ENOMEM); + } return &cmap->map; -free_cmap: - bpf_map_area_free(cmap); - return ERR_PTR(err); } static void get_cpu_map_entry(struct bpf_cpu_map_entry *rcpu) |