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| author | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2022-10-21 12:38:26 +0100 |
|---|---|---|
| committer | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2022-10-27 14:46:53 +0100 |
| commit | 28bd4285ad0f8ce6026583e9cc0a612018d461ba (patch) | |
| tree | 7a3aa851f83addae07337267feba755a07cade39 | |
| parent | 5eedf66625842a56c0ed7e16a1f79fda4b52b425 (diff) | |
| download | glibc-28bd4285ad0f8ce6026583e9cc0a612018d461ba.zip glibc-28bd4285ad0f8ce6026583e9cc0a612018d461ba.tar.gz glibc-28bd4285ad0f8ce6026583e9cc0a612018d461ba.tar.bz2 | |
cheri: elf: Fix segment mapping permissions
Ensure mmap returns pointers with RWX permission covering all segments.
These pointers later get restricted to RX and RW permission.
| -rw-r--r-- | elf/dl-map-segments.h | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/elf/dl-map-segments.h b/elf/dl-map-segments.h index ce51585..e25fb57 100644 --- a/elf/dl-map-segments.h +++ b/elf/dl-map-segments.h @@ -22,6 +22,13 @@ # include <cheri_perms.h> #endif +/* Allow RWX mprotect later, on CHERI this means RWX capability permission. */ +#ifdef PROT_MAX +# define PROT_MAX_RWX PROT_MAX (PROT_READ | PROT_WRITE | PROT_EXEC) +#else +# define PROT_MAX_RWX 0 +#endif + /* Map a segment and align it properly. */ static __always_inline elfptr_t @@ -29,7 +36,8 @@ _dl_map_segment (const struct loadcmd *c, ElfW(Addr) mappref, const size_t maplength, int fd) { if (__glibc_likely (c->mapalign <= GLRO(dl_pagesize))) - return (elfptr_t) __mmap ((void *) mappref, maplength, c->prot, + return (elfptr_t) __mmap ((void *) mappref, maplength, + c->prot|PROT_MAX_RWX, MAP_COPY|MAP_FILE, fd, c->mapoff); /* If the segment alignment > the page size, allocate enough space to @@ -38,7 +46,7 @@ _dl_map_segment (const struct loadcmd *c, ElfW(Addr) mappref, ? (maplength + c->mapalign) : (2 * c->mapalign)); elfptr_t map_start = (elfptr_t) __mmap ((void *) mappref, maplen, - PROT_NONE, + PROT_NONE|PROT_MAX_RWX, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); if (__glibc_unlikely ((void *) map_start == MAP_FAILED)) @@ -46,7 +54,7 @@ _dl_map_segment (const struct loadcmd *c, ElfW(Addr) mappref, elfptr_t map_start_aligned = ALIGN_UP (map_start, c->mapalign); map_start_aligned = (elfptr_t) __mmap ((void *) map_start_aligned, - maplength, c->prot, + maplength, c->prot|PROT_MAX_RWX, MAP_COPY|MAP_FILE|MAP_FIXED, fd, c->mapoff); if (__glibc_unlikely ((void *) map_start_aligned == MAP_FAILED)) @@ -137,7 +145,8 @@ _dl_map_segments (struct link_map *l, int fd, else { /* Need a single capability to cover all load segments. */ - void *p = __mmap ((void *) c->mapstart, maplength, c->prot, + void *p = __mmap ((void *) c->mapstart, maplength, + c->prot|PROT_MAX_RWX, MAP_FIXED|MAP_COPY|MAP_FILE, fd, c->mapoff); if (p == MAP_FAILED) |