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author | Mike Yuan <me@yhndnzj.com> | 2023-05-16 22:00:57 +0800 |
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committer | GitHub <noreply@github.com> | 2023-05-16 22:00:57 +0800 |
commit | 329f4b06f5124a8db042e8bd42fbc3265744aaa6 (patch) | |
tree | ebf0bd399aebe561ed2998920150d81250e2996b /src | |
parent | 0313c41068a362178190eac81f64b60223bb4c0c (diff) | |
parent | 3418ca21ed4dc08a26bed31d629e3fd4f9a2e191 (diff) | |
download | systemd-329f4b06f5124a8db042e8bd42fbc3265744aaa6.tar.gz |
Merge pull request #27659 from yuwata/memfd-seal
memfd-util: handle F_SEAL_EXEC flag
Diffstat (limited to 'src')
-rw-r--r-- | src/basic/memfd-util.c | 11 | ||||
-rw-r--r-- | src/basic/missing_fcntl.h | 8 | ||||
-rw-r--r-- | src/test/meson.build | 1 | ||||
-rw-r--r-- | src/test/test-memfd-util.c | 30 |
4 files changed, 48 insertions, 2 deletions
diff --git a/src/basic/memfd-util.c b/src/basic/memfd-util.c index 285abd41d3..8e6946642b 100644 --- a/src/basic/memfd-util.c +++ b/src/basic/memfd-util.c @@ -92,9 +92,15 @@ int memfd_map(int fd, uint64_t offset, size_t size, void **p) { } int memfd_set_sealed(int fd) { + int r; + assert(fd >= 0); - return RET_NERRNO(fcntl(fd, F_ADD_SEALS, F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_SEAL)); + r = RET_NERRNO(fcntl(fd, F_ADD_SEALS, F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_EXEC | F_SEAL_SEAL)); + if (r == -EINVAL) /* old kernel ? */ + r = RET_NERRNO(fcntl(fd, F_ADD_SEALS, F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_SEAL)); + + return r; } int memfd_get_sealed(int fd) { @@ -106,7 +112,8 @@ int memfd_get_sealed(int fd) { if (r < 0) return -errno; - return r == (F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_SEAL); + /* We ignore F_SEAL_EXEC here to support older kernels. */ + return FLAGS_SET(r, F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_SEAL); } int memfd_get_size(int fd, uint64_t *sz) { diff --git a/src/basic/missing_fcntl.h b/src/basic/missing_fcntl.h index 79e95a8f6f..24b2dc3119 100644 --- a/src/basic/missing_fcntl.h +++ b/src/basic/missing_fcntl.h @@ -25,6 +25,14 @@ #define F_SEAL_WRITE 0x0008 /* prevent writes */ #endif +#ifndef F_SEAL_FUTURE_WRITE +#define F_SEAL_FUTURE_WRITE 0x0010 /* prevent future writes while mapped */ +#endif + +#ifndef F_SEAL_EXEC +#define F_SEAL_EXEC 0x0020 /* prevent chmod modifying exec bits */ +#endif + #ifndef F_OFD_GETLK #define F_OFD_GETLK 36 #define F_OFD_SETLK 37 diff --git a/src/test/meson.build b/src/test/meson.build index 8e76df624d..7f8de2a2ce 100644 --- a/src/test/meson.build +++ b/src/test/meson.build @@ -112,6 +112,7 @@ simple_tests += files( 'test-log.c', 'test-logarithm.c', 'test-macro.c', + 'test-memfd-util.c', 'test-memory-util.c', 'test-mempool.c', 'test-mkdir.c', diff --git a/src/test/test-memfd-util.c b/src/test/test-memfd-util.c new file mode 100644 index 0000000000..f8e1b46075 --- /dev/null +++ b/src/test/test-memfd-util.c @@ -0,0 +1,30 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include <unistd.h> + +#include "errno-util.h" +#include "fd-util.h" +#include "memfd-util.h" +#include "string-util.h" +#include "tests.h" + +TEST(memfd_get_sealed) { +#define TEST_TEXT "this is some random test text we are going to write to a memfd" + _cleanup_close_ int fd = -EBADF; + + fd = memfd_new("test-memfd-get-sealed"); + if (fd < 0) { + assert_se(ERRNO_IS_NOT_SUPPORTED(fd)); + return; + } + + assert_se(write(fd, TEST_TEXT, strlen(TEST_TEXT)) == strlen(TEST_TEXT)); + /* we'll leave the read offset at the end of the memfd, the fdopen_independent() descriptors should + * start at the beginning anyway */ + + assert_se(memfd_get_sealed(fd) == 0); + assert_se(memfd_set_sealed(fd) >= 0); + assert_se(memfd_get_sealed(fd) > 0); +} + +DEFINE_TEST_MAIN(LOG_DEBUG); |