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| author | David Herrmann <dh.herrmann@gmail.com> | 2014-08-18 13:05:48 +0200 |
|---|---|---|
| committer | David Herrmann <dh.herrmann@gmail.com> | 2014-08-18 13:05:48 +0200 |
| commit | 23972f4244f7609658c2a17f85508d50e4739990 (patch) | |
| tree | ecc7b9895abf0c193cae5bf2deb6dcdfe8b77c04 | |
| parent | c7dab73a5fa6e775813765fe925caaa7c4e549fa (diff) | |
memfd: map unsealed files as MAP_SHARED
We need to map sealed files as MAP_PRIVATE so far as the kernel treats
MAP_SHARED as writable mapping (you can run mprotect(PROT_WRITE) at any
time on those). However, unsealed files must be mapped as MAP_SHARED.
Otherwise, we never end up writing to the real file.
| -rw-r--r-- | src/shared/memfd.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/src/shared/memfd.c b/src/shared/memfd.c index 6804b42361..d94c6268dd 100644 --- a/src/shared/memfd.c +++ b/src/shared/memfd.c @@ -176,7 +176,11 @@ int sd_memfd_map(sd_memfd *m, uint64_t offset, size_t size, void **p) { if (sealed < 0) return sealed; - q = mmap(NULL, size, sealed ? PROT_READ : PROT_READ|PROT_WRITE, MAP_PRIVATE, m->fd, offset); + if (sealed) + q = mmap(NULL, size, PROT_READ, MAP_PRIVATE, m->fd, offset); + else + q = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, m->fd, offset); + if (q == MAP_FAILED) return -errno; |