Re: [PHP4BETA] ABR: Array bounds read in ZTS mode + explanation.

On Mon, 27 Dec 1999, Zeev Suraski wrote: > On Mon, 27 Dec 1999, Thies C. Arntzen wrote: > > > **** Purify instrumented bin/nsd (pid 22145) **** > > ABR: Array bounds read (9440 times): > > * This is occurring while in thread 10: > > memcpy [rtlib.o] > > zend_hash_copy [zend_hash.c:861] > > compiler_globals_ctor [zend.c:247] > > allocate_new_resource [TSRM.c:200] > > ts_resource [TSRM.c:235] > > php_ns_request_handler [aolserver.c:500] > > * Reading 60 bytes from 0x264ec8 in the heap (44 bytes at 0x264ed8 illegal). > > * Address 0x264ec8 is at the beginning of a malloc'd block of 16 bytes. > > * This block was allocated from: > > malloc [rtlib.o] > > zend_hash_add_or_update [zend_hash.c:189] > > zend_register_functions [zend_API.c:698] > > zend_startup_builtin_functions [zend_builtin_functions.c:78] > > zend_startup [zend.c:363] > > > > problem is : > > > > zend_API.c line 698 > > if (zend_hash_add(target_function_table, ptr->fname, strlen(ptr->fname)+1, > > &internal_function, sizeof(zend_internal_function), NULL) == FAILURE) { > > unload=1; > > break; > > } > > > > zend.c line 238: > > zend_hash_copy(compiler_globals->function_table, global_function_table, NULL, > > &tmp_func, sizeof(zend_function)); > > > > > > but: sizeof(zend_function) > sizeof(zend_internal_function) so we're > > coying uninted memory (as purify tells us) in compiler_globals_ctor(). > > Well, that's one of the places that purify reports, correctly from its > point of view, but that we really don't care about. reading beyond a malloced block is not considered safe AFAIK. it is very, very unlikely but it could cause trouble. i can easily live with it, but i think it's bad style. how bad would be the penalty if we tried for a clean solution? tc > > Zeev > > -- > Zeev Suraski <zeev@zend.com> > http://www.zend.com/ > > Thies C. Arntzen "One Big-Mac, Small Fries and a Coke!" Digital Collections Phone +49 40 235350 Fax +49 40 23535180 Hammerbrookstr. 93 20097 Hamburg / Germany