From 8c2f6218f81ab5303e07bad4e13f181aa9581d92 Mon Sep 17 00:00:00 2001 From: Pavel Kozlov Date: Tue, 17 Oct 2023 14:01:22 +0400 Subject: setrlimit/getrlimit: fix prlimit64 syscall use for 32-bit CPUs Commit 95e38b37 ("add support for systems without legacy setrlimit/getrlimit syscalls") has added use of the prlimit64 syscall in getrlimit and setrlimit functions. This change causes memory corruption on getrlimit call for 32-bit CPUs like ARC, as ARC doesn't have ugetrlimit syscall and uses prlimit64. Also, setrlimit has been broken by prlimit64 call on 32-bit CPUs like, i386, ARM, ARC. For the prlimit64 syscall the kernel expects an rlimit struct with 64-bit fields, but on 32-bit CPUs without _FILE_OFFSET_BITS=64 the struct rlimit has 32-bit fields. Add safe implementations of getrlimit, setrlimit, prlimit for 32-bit CPUs with a local struct rlimit64 variable for use in the prlimit64 syscall. For 64-bit CPUs and configurations with _FILE_OFFSET_BITS=64 use getrlimit, setrlimit, prlimit as aliases to getrlimit64, setrlimit64 and prlimit64. Add a new function prlimit64. Tested on aarch64, arm, i386, arc. Fixes: 95e38b37 ("add support for systems without legacy setrlimit/getrlimit syscalls") Signed-off-by: Pavel Kozlov --- libc/sysdeps/linux/common/prlimit.c | 53 +++++++++++++++++++++++++++++++++---- 1 file changed, 48 insertions(+), 5 deletions(-) (limited to 'libc/sysdeps/linux/common/prlimit.c') diff --git a/libc/sysdeps/linux/common/prlimit.c b/libc/sysdeps/linux/common/prlimit.c index f44dc1664..f59ade3a3 100644 --- a/libc/sysdeps/linux/common/prlimit.c +++ b/libc/sysdeps/linux/common/prlimit.c @@ -17,14 +17,57 @@ #include #include -#include +#include // needed for NULL to be defined -#if defined __ASSUME_PRLIMIT64 +#if defined(__NR_prlimit64) && __WORDSIZE == 32 && !defined(__USE_FILE_OFFSET64) int prlimit (__pid_t pid, enum __rlimit_resource resource, - const struct rlimit *new_rlimit, struct rlimit *old_rlimit) + const struct rlimit *new_rlimit, struct rlimit *old_rlimit) { - return INLINE_SYSCALL (prlimit64, 4, pid, resource, new_rlimit, - old_rlimit); + struct rlimit64 new_rlimit64; + struct rlimit64 old_rlimit64; + int res; + + if (new_rlimit != NULL) { + if (new_rlimit->rlim_cur == RLIM_INFINITY) + new_rlimit64.rlim_cur = RLIM64_INFINITY; + else + new_rlimit64.rlim_cur = new_rlimit->rlim_cur; + if (new_rlimit->rlim_max == RLIM_INFINITY) + new_rlimit64.rlim_max = RLIM64_INFINITY; + else + new_rlimit64.rlim_max = new_rlimit->rlim_max; + } + + res = INLINE_SYSCALL (prlimit64, 4, pid, resource, &new_rlimit64, + &old_rlimit64); + + if (res == 0 && old_rlimit != NULL) { + /* If the syscall succeeds but the values do not fit into a + rlimit structure set EOVERFLOW errno and retrun -1. + With current Linux implementation of the prlimit64 syscall, + overflow can't happen. An extra condition has been added to get + the same behavior as in glibc for future potential overflows. */ + old_rlimit->rlim_cur = old_rlimit64.rlim_cur; + if (old_rlimit64.rlim_cur != old_rlimit->rlim_cur) { + if (new_rlimit == NULL && + old_rlimit64.rlim_cur != RLIM64_INFINITY) { + __set_errno(EOVERFLOW); + return -1; + } + old_rlimit->rlim_cur = RLIM_INFINITY; + } + old_rlimit->rlim_max = old_rlimit64.rlim_max; + if (old_rlimit64.rlim_max != old_rlimit->rlim_max) { + if (new_rlimit == NULL && + old_rlimit64.rlim_max != RLIM64_INFINITY) { + __set_errno(EOVERFLOW); + return -1; + } + old_rlimit->rlim_cur = RLIM_INFINITY; + } + } + + return res; } #endif -- cgit v1.2.3