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| author | T.J. Mercier <tjmercier@google.com> | 2026-07-22 13:54:42 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-07-24 14:53:16 -0700 |
| commit | be6f0d0bae229ebd03e9bfe736f78e2d6b35885f (patch) | |
| tree | 4e05b3c36e18ca6d91a6e1ff006e264fda0bf7f8 | |
| parent | 89d8006259b81dd25c962f6cc8d7ab268d6ea426 (diff) | |
| download | linux-next-be6f0d0bae229ebd03e9bfe736f78e2d6b35885f.tar.gz linux-next-be6f0d0bae229ebd03e9bfe736f78e2d6b35885f.zip | |
selftests: drv-net: ncdevmem: Open /dev/udmabuf O_RDONLY
Write permissions on the /dev/udmabuf device file are not required to
issue ioctls and allocate udmabufs. Applications should be opening this
file as O_RDONLY. The BPF dmabuf_iter selftest already does this. [1]
Users are pointing to these selftests as examples of how use udmabuf,
and encountering permission errors on systems where write permissions
are not available on /dev/udmabuf. Apply the principle of least
privilege to selftests which use udmabuf by removing the write access
mode from drivers/net/hw/ncdevmem.c.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/prog_tests/dmabuf_iter.c?h=v7.1#n49
Signed-off-by: T.J. Mercier <tjmercier@google.com>
Reviewed-by: Bobby Eshleman <bobbyeshleman@meta.com>
Link: https://patch.msgid.link/20260722205442.1894665-1-tjmercier@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | tools/testing/selftests/drivers/net/hw/ncdevmem.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/testing/selftests/drivers/net/hw/ncdevmem.c b/tools/testing/selftests/drivers/net/hw/ncdevmem.c index d96e8a3b5a65..ffe1d5c1fa4e 100644 --- a/tools/testing/selftests/drivers/net/hw/ncdevmem.c +++ b/tools/testing/selftests/drivers/net/hw/ncdevmem.c @@ -150,7 +150,7 @@ static struct memory_buffer *udmabuf_alloc(size_t size) ctx->size = size; - ctx->devfd = open("/dev/udmabuf", O_RDWR); + ctx->devfd = open("/dev/udmabuf", O_RDONLY); if (ctx->devfd < 0) { pr_err("[skip,no-udmabuf: Unable to access DMA buffer device file]"); goto err_free_ctx; |