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| author | Magnus Karlsson <magnus.karlsson@intel.com> | 2020-11-03 10:41:30 +0100 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2020-11-04 21:37:29 +0100 |
| commit | 25cf73b9ff88fd4608699a0313f820758b4c252d (patch) | |
| tree | 5159c3cd3c814ba59c3f19ec4ed4ebc157153cb2 /tools/lib/bpf/xsk.c | |
| parent | f78331f74cacb33d87cd60376dacc5bd397959e2 (diff) | |
| download | linux-25cf73b9ff88fd4608699a0313f820758b4c252d.tar.gz linux-25cf73b9ff88fd4608699a0313f820758b4c252d.tar.bz2 linux-25cf73b9ff88fd4608699a0313f820758b4c252d.zip | |
libbpf: Fix possible use after free in xsk_socket__delete
Fix a possible use after free in xsk_socket__delete that will happen
if xsk_put_ctx() frees the ctx. To fix, save the umem reference taken
from the context and just use that instead.
Fixes: 2f6324a3937f ("libbpf: Support shared umems between queues and devices")
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1604396490-12129-3-git-send-email-magnus.karlsson@gmail.com
Diffstat (limited to 'tools/lib/bpf/xsk.c')
| -rw-r--r-- | tools/lib/bpf/xsk.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index 504b7a85d445..9bc537d0b92d 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -892,6 +892,7 @@ void xsk_socket__delete(struct xsk_socket *xsk) { size_t desc_sz = sizeof(struct xdp_desc); struct xdp_mmap_offsets off; + struct xsk_umem *umem; struct xsk_ctx *ctx; int err; @@ -899,6 +900,7 @@ void xsk_socket__delete(struct xsk_socket *xsk) return; ctx = xsk->ctx; + umem = ctx->umem; if (ctx->prog_fd != -1) { xsk_delete_bpf_maps(xsk); close(ctx->prog_fd); @@ -918,11 +920,11 @@ void xsk_socket__delete(struct xsk_socket *xsk) xsk_put_ctx(ctx); - ctx->umem->refcount--; + umem->refcount--; /* Do not close an fd that also has an associated umem connected * to it. */ - if (xsk->fd != ctx->umem->fd) + if (xsk->fd != umem->fd) close(xsk->fd); free(xsk); } |