- 05 10月, 2012 1 次提交
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由 Rich Felker 提交于
the design for TLS in dynamic-linked programs is mostly complete too, but I have not yet implemented it. cost is nonzero but still low for programs which do not use TLS and/or do not use threads (a few hundred bytes of new code, plus dependency on memcpy). i believe it can be made smaller at some point by merging __init_tls and __init_security into __libc_start_main and avoiding duplicate auxv-parsing code. at the same time, I've also slightly changed the logic pthread_create uses to allocate guard pages to ensure that guard pages are not counted towards commit charge.
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- 30 9月, 2012 2 次提交
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由 Rich Felker 提交于
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由 Rich Felker 提交于
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- 07 9月, 2012 1 次提交
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由 Rich Felker 提交于
to deal with the fact that the public headers may be used with pre-c99 compilers, __restrict is used in place of restrict, and defined appropriately for any supported compiler. we also avoid the form [restrict] since older versions of gcc rejected it due to a bug in the original c99 standard, and instead use the form *restrict.
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- 27 8月, 2012 2 次提交
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由 Rich Felker 提交于
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由 Rich Felker 提交于
based on patches submitted by boris brezillon. this commit also fixes the issue whereby the main application and libc don't have the address ranges of their mappings stored, which was theoretically a problem for RTLD_NEXT support in dlsym; it didn't actually matter because libc never calls dlsym, and it seemed to be doing the right thing (by chance) for symbols in the main program as well.
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- 26 8月, 2012 5 次提交
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由 Rich Felker 提交于
wrong hash was being passed; just a copy/paste error. did not affect lookups in the global namespace; this is probably why it was not caught in testing.
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由 Rich Felker 提交于
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由 Rich Felker 提交于
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由 Rich Felker 提交于
previously, this usage could lead to a crash if the thread pointer was still uninitialized, and otherwise would just cause the canary to be zero (less secure).
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由 Rich Felker 提交于
based on the patches contributed by boris brezillon.
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- 19 8月, 2012 1 次提交
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由 Rich Felker 提交于
before, only the first library that failed to load or symbol that failed to resolve was reported, and then the dynamic linker immediately exited. when attempting to fix a library compatibility issue, this is about the worst possible behavior. now we print all errors as they occur and exit at the very end if errors were encountered.
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- 08 8月, 2012 1 次提交
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由 Rich Felker 提交于
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- 06 8月, 2012 3 次提交
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由 Rich Felker 提交于
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由 Rich Felker 提交于
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由 Rich Felker 提交于
not heavily tested, but the basics are working. the basic concept is that the dynamic linker entry point code invokes a pure-PIC (no global accesses) C function in reloc.h to perform the early GOT relocations needed to make the dynamic linker itself functional, then invokes __dynlink like on other archs. since mips uses some ugly arch-specific hacks to optimize relocating the GOT (rather than just using the normal DT_REL[A] tables like on other archs), the dynamic linker has been modified slightly to support calling arch-specific relocation code in reloc.h. most of the actual mips-specific behavior was developed by reading the output of readelf on libc.so and simple executable files. i could not find good reference information on which relocation types need to be supported or their semantics, so it's possible that some legitimate usage cases will not work yet.
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- 05 8月, 2012 3 次提交
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由 Rich Felker 提交于
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由 Rich Felker 提交于
changing the string printed for the dso name is not a regression; the old code was simply using the wrong dso name (head rather than the dso currently being relocated). this will be fixed in a later commit.
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由 Rich Felker 提交于
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- 13 7月, 2012 1 次提交
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由 Rich Felker 提交于
use the main program's PT_INTERP header if possible, since this is sure to be a correct (and hopefully absolute) pathname.
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- 11 7月, 2012 2 次提交
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由 Rich Felker 提交于
if libc.a is compiled PIC for use in static PIE code, this should not cause the dynamic linker (which still does not support static-linked main program) to be built into libc.a.
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由 Rich Felker 提交于
most importantly, the name for such libs was being set from an uninitialized buffer. also, shortname always had an initial '/' character, making it useless for looking up already-loaded libraries by name, and thus causing repeated searches through the library path. major changes now: - shortname is the base name for library lookups with no explicit pathname. it's initially clear for libraries loaded with an explicit pathname (and for the main program), but will be set if the same library (detected via inodes match) is later found by a search. - exact name match is never used to identify libraries loaded with an explicit pathname. in this case, there's no explicit search, so we can just stat the file and check for inode match.
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- 08 7月, 2012 1 次提交
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由 Rich Felker 提交于
previously this was being handled the same as a library-specific, dependency-order lookup on the next library in the global chain, which is likely to be utterly meaningless. instead the lookup needs to be in the global namespace, but omitting the initial portion of the global library chain up through the calling library.
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- 10 6月, 2012 1 次提交
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由 Rich Felker 提交于
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- 06 6月, 2012 1 次提交
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由 Rich Felker 提交于
the error will propagate up and be printed to the user at program start time; at runtime, dlopen will just fail and leave a message for dlerror. previously, if mprotect failed, subsequent attempts to perform relocations would crash the program. this was resulting in an increasing number of false bug reports on grsec systems where rwx permission is not possible in cases where users were wrongly attempting to use non-PIC code in shared libraries. supporting that usage is in theory possible, but the x86_64 toolchain does not even support textrels, and the cost of keeping around the necessary information to handle textrels without rwx permissions is disproportionate to the benefit (which is essentially just supporting broken library setups on grsec machines). also, i unified the error-out code in map_library now that there are 3 places from which munmap might have to be called.
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- 28 5月, 2012 1 次提交
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由 Rich Felker 提交于
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- 05 5月, 2012 1 次提交
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由 Rich Felker 提交于
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- 04 5月, 2012 1 次提交
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由 Rich Felker 提交于
pthread structure has been adjusted to match the glibc/GCC abi for where the canary is stored on i386 and x86_64. it will need variants for other archs to provide the added security of the canary's entropy, but even without that it still works as well as the old "minimal" ssp support. eventually such changes will be made anyway, since they are also needed for GCC/C11 thread-local storage support (not yet implemented). care is taken not to attempt initializing the thread pointer unless the program actually uses SSP (by reference to __stack_chk_fail).
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- 25 4月, 2012 2 次提交
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由 Rich Felker 提交于
provide the minimal level of dynamic linker-to-debugger glue needed to let gdb find loaded libraries and load their symbols.
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由 Rich Felker 提交于
the code is written to pre-init the thread pointer in static linked programs that pull in __stack_chk_fail or dynamic-linked programs that lookup the symbol. no explicit canary is set; the canary will be whatever happens to be in the thread structure at the offset gcc hard-coded. this can be improved later.
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- 24 4月, 2012 1 次提交
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由 Rich Felker 提交于
note that dlerror is specified to be non-thread-safe, so no locking is performed on the error flag or message aside from the rwlock already held by dlopen or dlsym. if 2 invocations of dlsym are generating errors at the same time, they could clobber each other's results, but the resulting string, albeit corrupt, will still be null-terminated. any use of dlerror in such a situation could not be expected to give meaningful results anyway.
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- 23 3月, 2012 1 次提交
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由 Rich Felker 提交于
the error status is required to be sticky after failure of dlopen or dlsym until cleared by dlerror. applications and especially libraries should never rely on this since it is not thread-safe and subject to race conditions, but glib does anyway.
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- 08 2月, 2012 2 次提交
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由 Rich Felker 提交于
i'm not sure that it's "correct" for dlopen to block cancellation when calling constructors for libraries it loads, but it sure seems like the right thing. in any case, dlopen itself needs cancellation blocked.
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由 Rich Felker 提交于
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- 07 2月, 2012 2 次提交
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由 Rich Felker 提交于
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由 Rich Felker 提交于
this is mainly in hopes of supporting c++ (not yet possible for other reasons) but will also help applications/libraries which use (and more often, abuse) the gcc __attribute__((__constructor__)) feature in "C" code. x86_64 and arm versions of the new startup asm are untested and may have minor problems.
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- 03 2月, 2012 1 次提交
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由 Rich Felker 提交于
these don't work (or do anything at all) but at least make it possible to static link programs that insist on "having" dynamic loading support...as long as they don't actually need to use it. adding real support for dlopen/dlsym with static linking is going to be significantly more difficult...
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- 24 1月, 2012 1 次提交
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由 Rich Felker 提交于
this issue affected programs which use global variables exported by non-libc libraries.
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- 23 1月, 2012 2 次提交
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由 Rich Felker 提交于
even with this change, PIE will not work yet due to deficiencies in the crt1.o startup code.
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由 Rich Felker 提交于
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