2. It prevents unknowingly escalating a supply-chain attack. If a malware is somehow embedded in the compiler, it will be able to 1) read secret keys used by developers to sign binary packages, and 2) embed those secret keys in the compiler output (likely set for distribution).
Of course, that specific scenario can already be prevented in theory, using file permissions. But more security will not hurt.
On 18/07/2024 19:55, Theo de Raadt wrote:
Please tell me what security problem unveil is solving in this program. Vevy Kod <vevy...@laposte.net> wrote:How about adding an environment variable containing all directories where headers can be found ? If it is not provided, we can fall back to the per-file algorithm, possibly going above limit. If a user goes above that limit, they can provide their own list of directories. And in the worst case, they can simply set it to '/', giving themselves read access to everything. On 18/07/2024 17:43, Lorenz (xha) wrote:the HARE_TD_<files> are the "typedef" files, basically the equivalent to C headers, but automatically generated by the compiler so we can do resolution of types/functions/etc. in dependencies without having to look at the source files themselves. i doubt that anyone is ever going to make use of more than 125 imports. the problem is that i cannot simply restict that to one folder. they could be anywhere (even though they are not usually). that'd complicate the patch a lot for... allowing more than 125 imports? the error message will not be particularly hard to read; i guess if someone really hits the limit, we can do something about it then? we don't want to do anything in upstream harec because we want to keep it to the POSIX subset. On Thu, Jul 18, 2024 at 09:29:39AM -0600, Theo de Raadt wrote:Tobias Heider <tobias.hei...@stusta.de> wrote:I think unveil might still be useful.I don't think so.As I understand Theo the problem is just that calling unveil per-input file to grant read access won't work. Restricting write and create permissions to the single well-known output directory still makes sense to me.The set of library functions used is pretty small, so it should be easy enough to reason about adding pledge. $ nm -s /usr/local/bin/harec | awk '/^ *U / { print $2 }' | column __assert2 atexit fseek memset strerror __errno bsearch fstat open_memstream strlen __isinf calloc getenv optarg strncmp __isinff exit getline optind strtod __isinfl fclose getopt perror strtoul __isnan feof isalnum qsort strtoumax __isnanf fgetc isalpha realloc vfprintf __isnanl fileno isatty snprintf vsnprintf __isthreaded fmemopen isdigit stat __sF fopen isprint strchr _csu_finish fread memcmp strcmp abort free memcpy strdupSo the undocumented, un-exported, unveil limit today is 128. This comes with a cost, so we will not be increasing it. Enough setenv, enough arguments, and it fails. Now how does someone "workaround" it in their build tooling? THAT "workaround" is what makes the solution. This is not what unveil is intended to support.
OpenPGP_0x02796D87FACEDF43.asc
Description: OpenPGP public key
OpenPGP_signature.asc
Description: OpenPGP digital signature
