diff options
| author | Josh Triplett <josh@joshtriplett.org> | 2014-04-03 14:48:27 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-04-03 16:21:05 -0700 |
| commit | 69369a7003735d0d8ef22097e27a55a8bad9557a (patch) | |
| tree | b7638899a8e81fc18a497791685f1b571d733896 | |
| parent | 8f6c5ffc8987f4f5b5a3e9d557d94bbf3a9bf216 (diff) | |
fs, kernel: permit disabling the uselib syscall
uselib hasn't been used since libc5; glibc does not use it. Support
turning it off.
When disabled, also omit the load_elf_library implementation from
binfmt_elf.c, which only uselib invokes.
bloat-o-meter:
add/remove: 0/4 grow/shrink: 0/1 up/down: 0/-785 (-785)
function old new delta
padzero 39 36 -3
uselib_flags 20 - -20
sys_uselib 168 - -168
SyS_uselib 168 - -168
load_elf_library 426 - -426
The new CONFIG_USELIB defaults to `y'.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/binfmt_elf.c | 9 | ||||
| -rw-r--r-- | fs/exec.c | 2 | ||||
| -rw-r--r-- | init/Kconfig | 10 | ||||
| -rw-r--r-- | kernel/sys_ni.c | 1 |
4 files changed, 21 insertions, 1 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 67be2951b98a..0f59799fa105 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -46,10 +46,15 @@ #endif static int load_elf_binary(struct linux_binprm *bprm); -static int load_elf_library(struct file *); static unsigned long elf_map(struct file *, unsigned long, struct elf_phdr *, int, int, unsigned long); +#ifdef CONFIG_USELIB +static int load_elf_library(struct file *); +#else +#define load_elf_library NULL +#endif + /* * If we don't support core dumping, then supply a NULL so we * don't even try. @@ -1005,6 +1010,7 @@ out_free_ph: goto out; } +#ifdef CONFIG_USELIB /* This is really simpleminded and specialized - we are loading an a.out library that is given an ELF header. */ static int load_elf_library(struct file *file) @@ -1083,6 +1089,7 @@ out_free_ph: out: return error; } +#endif /* #ifdef CONFIG_USELIB */ #ifdef CONFIG_ELF_CORE /* diff --git a/fs/exec.c b/fs/exec.c index 4f59402fdda5..25dfeba6d55f 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -97,6 +97,7 @@ static inline void put_binfmt(struct linux_binfmt * fmt) module_put(fmt->module); } +#ifdef CONFIG_USELIB /* * Note that a shared library must be both readable and executable due to * security reasons. @@ -156,6 +157,7 @@ exit: out: return error; } +#endif /* #ifdef CONFIG_USELIB */ #ifdef CONFIG_MMU /* diff --git a/init/Kconfig b/init/Kconfig index e45cc62904b3..8114a06117e3 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -273,6 +273,16 @@ config FHANDLE get renamed. Enables open_by_handle_at(2) and name_to_handle_at(2) syscalls. +config USELIB + bool "uselib syscall" + default y + help + This option enables the uselib syscall, a system call used in the + dynamic linker from libc5 and earlier. glibc does not use this + system call. If you intend to run programs built on libc5 or + earlier, you may need to enable this syscall. Current systems + running glibc can safely disable this. + config AUDIT bool "Auditing support" depends on NET diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c index 74395a95b7e9..bc8d1b74a6b9 100644 --- a/kernel/sys_ni.c +++ b/kernel/sys_ni.c @@ -152,6 +152,7 @@ cond_syscall(sys_process_vm_readv); cond_syscall(sys_process_vm_writev); cond_syscall(compat_sys_process_vm_readv); cond_syscall(compat_sys_process_vm_writev); +cond_syscall(sys_uselib); /* arch-specific weak syscall entries */ cond_syscall(sys_pciconfig_read); |