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| author | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2020-06-22 10:56:38 +0100 |
|---|---|---|
| committer | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2020-07-08 14:28:53 +0100 |
| commit | c7aa8596de86fb667914ccb95c10495ad056ff96 (patch) | |
| tree | 1d49bc2092f2cbb06b761f7f047626e45195082d /sysdeps/generic | |
| parent | c1e63c7214aaef99039068da384a0ab3abc176f2 (diff) | |
| download | glibc-c7aa8596de86fb667914ccb95c10495ad056ff96.tar.gz | |
rtld: Clean up PT_NOTE and add PT_GNU_PROPERTY handling
Add generic code to handle PT_GNU_PROPERTY notes. Invalid
content is ignored, _dl_process_pt_gnu_property is always called
after PT_LOAD segments are mapped and it has no failure modes.
Currently only one NT_GNU_PROPERTY_TYPE_0 note is handled, which
contains target specific properties: the _dl_process_gnu_property
hook is called for each property.
The old _dl_process_pt_note and _rtld_process_pt_note differ in how
the program header is read. The old _dl_process_pt_note is called
before PT_LOAD segments are mapped and _rtld_process_pt_note is called
after PT_LOAD segments are mapped. The old _rtld_process_pt_note is
removed and _dl_process_pt_note is always called after PT_LOAD
segments are mapped and now it has no failure modes.
The program headers are scanned backwards so that PT_NOTE can be
skipped if PT_GNU_PROPERTY exists.
Co-Authored-By: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Diffstat (limited to 'sysdeps/generic')
| -rw-r--r-- | sysdeps/generic/dl-prop.h | 23 | ||||
| -rw-r--r-- | sysdeps/generic/ldsodefs.h | 4 |
2 files changed, 15 insertions, 12 deletions
diff --git a/sysdeps/generic/dl-prop.h b/sysdeps/generic/dl-prop.h index 6b0f2aa95a..f1cf576fe3 100644 --- a/sysdeps/generic/dl-prop.h +++ b/sysdeps/generic/dl-prop.h @@ -20,11 +20,11 @@ #define _DL_PROP_H /* The following functions are used by the dynamic loader and the - dlopen machinery to process PT_NOTE entries in the binary or - shared object. The notes can be used to change the behaviour of - the loader, and as such offer a flexible mechanism for hooking in - various checks related to ABI tags or implementing "flag day" ABI - transitions. */ + dlopen machinery to process PT_NOTE and PT_GNU_PROPERTY entries in + the binary or shared object. The notes can be used to change the + behaviour of the loader, and as such offer a flexible mechanism + for hooking in various checks related to ABI tags or implementing + "flag day" ABI transitions. */ static inline void __attribute__ ((always_inline)) _rtld_main_check (struct link_map *m, const char *program) @@ -36,17 +36,16 @@ _dl_open_check (struct link_map *m) { } -#ifdef FILEBUF_SIZE -static inline int __attribute__ ((always_inline)) -_dl_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph, - int fd, struct filebuf *fbp) +static inline void __attribute__ ((always_inline)) +_dl_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph) { - return 0; } -#endif +/* Called for each property in the NT_GNU_PROPERTY_TYPE_0 note of L, + processing of the properties continues until this returns 0. */ static inline int __attribute__ ((always_inline)) -_rtld_process_pt_note (struct link_map *l, const ElfW(Phdr) *ph) +_dl_process_gnu_property (struct link_map *l, uint32_t type, uint32_t datasz, + void *data) { return 0; } diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h index d08b97a5ef..c525ffa12c 100644 --- a/sysdeps/generic/ldsodefs.h +++ b/sysdeps/generic/ldsodefs.h @@ -910,6 +910,10 @@ extern void _dl_setup_hash (struct link_map *map) attribute_hidden; extern void _dl_rtld_di_serinfo (struct link_map *loader, Dl_serinfo *si, bool counting); +/* Process PT_GNU_PROPERTY program header PH in module L after + PT_LOAD segments are mapped. */ +void _dl_process_pt_gnu_property (struct link_map *l, const ElfW(Phdr) *ph); + /* Search loaded objects' symbol tables for a definition of the symbol referred to by UNDEF. *SYM is the symbol table entry containing the |