[uclibc-ng-devel] [PATCH] setrlimit/getrlimit: fix prlimit64 syscall use for 32-bit CPUs

From: Pavel Kozlov &lt;pavel.kozlov(a)synopsys.com&gt; 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 &lt;pavel.kozlov(a)synopsys.com&gt; --- include/sys/resource.h | 4 ++ libc/sysdeps/linux/common/getrlimit.c | 55 ++++++++++++++++++------- libc/sysdeps/linux/common/getrlimit64.c | 26 ++++++++++-- libc/sysdeps/linux/common/prlimit.c | 53 +++++++++++++++++++++--- libc/sysdeps/linux/common/prlimit64.c | 36 ++++++++++++++++ libc/sysdeps/linux/common/setrlimit.c | 41 +++++++++++------- libc/sysdeps/linux/common/setrlimit64.c | 24 +++++++++-- 7 files changed, 197 insertions(+), 42 deletions(-) create mode 100644 libc/sysdeps/linux/common/prlimit64.c diff --git a/include/sys/resource.h b/include/sys/resource.h index 00c63ff0f1e5..e9fac2c656bf 100644 --- a/include/sys/resource.h +++ b/include/sys/resource.h @@ -106,6 +106,10 @@ libc_hidden_proto(setpriority) extern int prlimit (__pid_t __pid, enum __rlimit_resource __resource, const struct rlimit *__new_limit, struct rlimit *__old_limit) __THROW; + +extern int prlimit64 (__pid_t __pid, enum __rlimit_resource __resource, + const struct rlimit64 *__new_limit, + struct rlimit64 *__old_limit) __THROW; #endif __END_DECLS diff --git a/libc/sysdeps/linux/common/getrlimit.c b/libc/sysdeps/linux/common/getrlimit.c index ad3f4a0e494d..46726fcbd94f 100644 --- a/libc/sysdeps/linux/common/getrlimit.c +++ b/libc/sysdeps/linux/common/getrlimit.c @@ -24,21 +24,53 @@ int getrlimit(__rlimit_resource_t resource, struct rlimit *rlimits) { return __syscall_ugetrlimit(resource, rlimits); } +libc_hidden_def(getrlimit) -#else - -# if !defined(__UCLIBC_HANDLE_OLDER_RLIMIT__) +#elif defined(__NR_prlimit64) +/* Use prlimit64 if present, the prlimit64 syscall is free from a back + compatibility stuff for an old getrlimit */ -# if defined(__NR_prlimit64) +# if __WORDSIZE == 32 && !defined(__USE_FILE_OFFSET64) +/* If struct rlimit has 64-bit fields (if __WORDSIZE == 64 or __USE_FILE_OFFSET64 + is defined), then use getrlimit as an alias to getrlimit64, see getrlimit64.c */ int getrlimit(__rlimit_resource_t resource, struct rlimit *rlimits) { - return INLINE_SYSCALL (prlimit64, 4, 0, resource, NULL, rlimits); + struct rlimit64 rlimits64; + int res = INLINE_SYSCALL (prlimit64, 4, 0, resource, NULL, &rlimits64); + + if (res == 0) { + /* If the syscall succeeds but the values do not fit into a + rlimit structure set EOVERFLOW errno and retrun -1. */ + rlimits->rlim_cur = rlimits64.rlim_cur; + if (rlimits64.rlim_cur != rlimits->rlim_cur) { + if (rlimits64.rlim_cur != RLIM64_INFINITY) { + __set_errno(EOVERFLOW); + return -1; + } + rlimits->rlim_cur = RLIM_INFINITY; + } + + rlimits->rlim_max = rlimits64.rlim_max; + if (rlimits64.rlim_max != rlimits->rlim_max) { + if (rlimits64.rlim_max != RLIM64_INFINITY) { + __set_errno(EOVERFLOW); + return -1; + } + rlimits->rlim_max = RLIM_INFINITY; + } + } + return res; } -# else +libc_hidden_def(getrlimit) +# endif + +#else + +# if !defined(__UCLIBC_HANDLE_OLDER_RLIMIT__) + /* We don't need to wrap getrlimit() */ _syscall2(int, getrlimit, __rlimit_resource_t, resource, struct rlimit *, rlim) -# endif # else @@ -51,11 +83,7 @@ int getrlimit(__rlimit_resource_t resource, struct rlimit *rlimits) { int result; -# if defined(__NR_prlimit64) - result = INLINE_SYSCALL (prlimit64, 4, 0, resource, NULL, rlimits); -# else result = __syscall_getrlimit(resource, rlimits); -# endif if (result == -1) return result; @@ -69,9 +97,6 @@ int getrlimit(__rlimit_resource_t resource, struct rlimit *rlimits) return result; } # endif -#endif -libc_hidden_def(getrlimit) -#if __WORDSIZE == 64 -strong_alias_untyped(getrlimit, getrlimit64) +libc_hidden_def(getrlimit) #endif diff --git a/libc/sysdeps/linux/common/getrlimit64.c b/libc/sysdeps/linux/common/getrlimit64.c index be98098a1ee0..47f1410fb3d9 100644 --- a/libc/sysdeps/linux/common/getrlimit64.c +++ b/libc/sysdeps/linux/common/getrlimit64.c @@ -17,14 +17,31 @@ #include <_lfs_64.h> #include <bits/wordsize.h> +#include <sys/resource.h> +#include <sys/syscall.h> +#include <stddef.h> // needed for NULL to be defined -/* the regular getrlimit will work just fine for 64bit users */ -#if __WORDSIZE == 32 -# include <sys/resource.h> +#if defined(__NR_prlimit64) + +/* the regular prlimit64 will work just fine for 64-bit users */ +int getrlimit64 (__rlimit_resource_t resource, struct rlimit64 *rlimits) +{ + return INLINE_SYSCALL (prlimit64, 4, 0, resource, NULL, rlimits); +} + +# if !defined(__NR_ugetrlimit) && (__WORDSIZE == 64 || defined (__USE_FILE_OFFSET64)) +/* If getrlimit is not implemented through the __NR_ugetrlimit and size of + rlimit_t == rlimit64_t then use getrlimit as an alias to getrlimit64 */ +strong_alias_untyped(getrlimit64, getrlimit) +libc_hidden_def(getrlimit) +# endif + +#else /* Put the soft and hard limits for RESOURCE in *RLIMITS. - Returns 0 if successful, -1 if not (and sets errno). */ + Returns 0 if successful, -1 if not (and sets errno). + The regular getrlimit will work just fine for 64-bit users */ int getrlimit64 (__rlimit_resource_t resource, struct rlimit64 *rlimits) { struct rlimit rlimits32; @@ -44,3 +61,4 @@ int getrlimit64 (__rlimit_resource_t resource, struct rlimit64 *rlimits) return 0; } #endif + diff --git a/libc/sysdeps/linux/common/prlimit.c b/libc/sysdeps/linux/common/prlimit.c index f44dc166492e..f59ade3a379c 100644 --- a/libc/sysdeps/linux/common/prlimit.c +++ b/libc/sysdeps/linux/common/prlimit.c @@ -17,14 +17,57 @@ #include <sys/resource.h> #include <sysdep.h> -#include <bits/kernel-features.h> +#include <stddef.h> // 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 diff --git a/libc/sysdeps/linux/common/prlimit64.c b/libc/sysdeps/linux/common/prlimit64.c new file mode 100644 index 000000000000..6f57b939eeca --- /dev/null +++ b/libc/sysdeps/linux/common/prlimit64.c @@ -0,0 +1,36 @@ +/* Copyright (C) 2023 uClibc-ng + * An prlimit64() - get/set resource limits Linux specific syscall. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Library General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Library General Public License for more details. + * + * You should have received a copy of the GNU Library General Public + * License along with this library; if not, see + * <http://www.gnu.org/licenses/>. + */ + +#include <sys/resource.h> +#include <sysdep.h> + +#if defined(__NR_prlimit64) + +int +prlimit64 (__pid_t pid, enum __rlimit_resource resource, + const struct rlimit64 *new_rlimit, struct rlimit64 *old_rlimit) +{ + return INLINE_SYSCALL (prlimit64, 4, pid, resource, new_rlimit, + old_rlimit); +} + +# if __WORDSIZE == 64 || defined (__USE_FILE_OFFSET64) +strong_alias_untyped(prlimit64, prlimit) +# endif + +#endif \ No newline at end of file diff --git a/libc/sysdeps/linux/common/setrlimit.c b/libc/sysdeps/linux/common/setrlimit.c index 8381afc617fd..9c6707235f3e 100644 --- a/libc/sysdeps/linux/common/setrlimit.c +++ b/libc/sysdeps/linux/common/setrlimit.c @@ -23,21 +23,41 @@ int setrlimit(__rlimit_resource_t resource, const struct rlimit *rlimits) { return __syscall_usetrlimit(resource, rlimits); } +libc_hidden_def(setrlimit) -#else +#elif defined(__NR_prlimit64) -# if !defined(__UCLIBC_HANDLE_OLDER_RLIMIT__) +/* Use prlimit64 if present, the prlimit64 syscall is free from a back + compatibility stuff for setrlimit */ -# if defined(__NR_prlimit64) + # if __WORDSIZE == 32 && !defined(__USE_FILE_OFFSET64) +/* If struct rlimit has 64-bit fields (if __WORDSIZE == 64 or __USE_FILE_OFFSET64 + is defined), then use setrlimit as an alias to setrlimit64, see setrlimit64.c */ int setrlimit(__rlimit_resource_t resource, const struct rlimit *rlimits) { - return INLINE_SYSCALL (prlimit64, 4, 0, resource, rlimits, NULL); + struct rlimit64 rlimits64; + + if (rlimits->rlim_cur == RLIM_INFINITY) + rlimits64.rlim_cur = RLIM64_INFINITY; + else + rlimits64.rlim_cur = rlimits->rlim_cur; + if (rlimits->rlim_max == RLIM_INFINITY) + rlimits64.rlim_max = RLIM64_INFINITY; + else + rlimits64.rlim_max = rlimits->rlim_max; + + return INLINE_SYSCALL (prlimit64, 4, 0, resource, &rlimits64, NULL); } -# else +libc_hidden_def(setrlimit) +# endif + +#else + +# if !defined(__UCLIBC_HANDLE_OLDER_RLIMIT__) + /* We don't need to wrap setrlimit() */ _syscall2(int, setrlimit, __rlimit_resource_t, resource, const struct rlimit *, rlim) -# endif # else @@ -66,16 +86,9 @@ int setrlimit(__rlimit_resource_t resource, const struct rlimit *rlimits) RLIM_INFINITY >> 1); rlimits_small.rlim_max = MIN((unsigned long int) rlimits->rlim_max, RLIM_INFINITY >> 1); -# if defined(__NR_prlimit64) - return INLINE_SYSCALL (prlimit64, 4, 0, resource, &rlimits_small, NULL); -# else return __syscall_setrlimit(resource, &rlimits_small); -# endif } # endif -#endif -libc_hidden_def(setrlimit) -#if __WORDSIZE == 64 -strong_alias_untyped(setrlimit, setrlimit64) +libc_hidden_def(setrlimit) #endif diff --git a/libc/sysdeps/linux/common/setrlimit64.c b/libc/sysdeps/linux/common/setrlimit64.c index fee14f4ad4b2..3446c58fee12 100644 --- a/libc/sysdeps/linux/common/setrlimit64.c +++ b/libc/sysdeps/linux/common/setrlimit64.c @@ -17,15 +17,31 @@ #include <_lfs_64.h> #include <bits/wordsize.h> +#include <sys/resource.h> +#include <sys/syscall.h> +#include <stddef.h> // needed for NULL to be defined -/* the regular setrlimit will work just fine for 64bit users */ -#if __WORDSIZE == 32 -# include <sys/resource.h> +#if defined(__NR_prlimit64) + +int setrlimit64 (__rlimit_resource_t resource, const struct rlimit64 *rlimits) +{ + return INLINE_SYSCALL (prlimit64, 4, 0, resource, rlimits, NULL); +} + +# if !defined(__NR_usetrlimit) && (__WORDSIZE == 64 || defined (__USE_FILE_OFFSET64)) +/* If setrlimit is not implemented through the __NR_usetrlimit and size of + rlimit_t == rlimit64_t then use setrlimit as an alias to setrlimit64 */ +strong_alias_untyped(setrlimit64, setrlimit) +libc_hidden_def(setrlimit) +# endif + +#else /* Set the soft and hard limits for RESOURCE to *RLIMITS. Only the super-user can increase hard limits. - Return 0 if successful, -1 if not (and sets errno). */ + Return 0 if successful, -1 if not (and sets errno). + The regular setrlimit will work just fine for 64bit users */ int setrlimit64 (__rlimit_resource_t resource, const struct rlimit64 *rlimits) { struct rlimit rlimits32; -- 2.25.1