Ensure raw fchmod/fchmodat syscalls are hidden.
In https://android-review.googlesource.com/#/c/127908/5/libc/SYSCALLS.TXT@116
Elliott said:
for LP64 these will be hidden. for LP32 we were cowards and left
them all public for compatibility (though i don't think we ever
dremeled to see whether it was needed). we don't have an easy
way to recognize additions, though, so we can't prevent adding
new turds.
Add a mechanism to prevent the adding of new turds, and use that
mechanism on the fchmod/fchmodat system calls.
Bug: 19233951
Change-Id: I98f98345970b631a379f348df57858f9fc3d57c0
diff --git a/libc/SYSCALLS.TXT b/libc/SYSCALLS.TXT
index d68a00f..aae7de7 100644
--- a/libc/SYSCALLS.TXT
+++ b/libc/SYSCALLS.TXT
@@ -113,7 +113,7 @@
int __fcntl64:fcntl64(int, int, void*) arm,mips,x86
int fcntl(int, int, void*) arm64,mips64,x86_64
int flock(int, int) all
-int __fchmod:fchmod(int, mode_t) all
+int ___fchmod:fchmod(int, mode_t) all
int dup(int) all
int pipe2(int*, int) all
int dup3(int, int, int) all
@@ -131,7 +131,7 @@
int __openat:openat(int, const char*, int, mode_t) all
int faccessat(int, const char*, int, int) all
-int __fchmodat:fchmodat(int, const char*, mode_t) all
+int ___fchmodat:fchmodat(int, const char*, mode_t) all
int fchownat(int, const char*, uid_t, gid_t, int) all
int fstatat64|fstatat:fstatat64(int, const char*, struct stat*, int) arm,mips,x86
int fstatat64|fstatat:newfstatat(int, const char*, struct stat*, int) arm64,x86_64
diff --git a/libc/arch-arm/syscalls/__fchmod.S b/libc/arch-arm/syscalls/___fchmod.S
similarity index 84%
rename from libc/arch-arm/syscalls/__fchmod.S
rename to libc/arch-arm/syscalls/___fchmod.S
index ff888a1..c6da4f8 100644
--- a/libc/arch-arm/syscalls/__fchmod.S
+++ b/libc/arch-arm/syscalls/___fchmod.S
@@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
-ENTRY(__fchmod)
+ENTRY(___fchmod)
mov ip, r7
ldr r7, =__NR_fchmod
swi #0
@@ -11,4 +11,5 @@
bxls lr
neg r0, r0
b __set_errno_internal
-END(__fchmod)
+END(___fchmod)
+.hidden ___fchmod
diff --git a/libc/arch-arm/syscalls/__fchmodat.S b/libc/arch-arm/syscalls/___fchmodat.S
similarity index 82%
rename from libc/arch-arm/syscalls/__fchmodat.S
rename to libc/arch-arm/syscalls/___fchmodat.S
index 4d10f00..91bbda5 100644
--- a/libc/arch-arm/syscalls/__fchmodat.S
+++ b/libc/arch-arm/syscalls/___fchmodat.S
@@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
-ENTRY(__fchmodat)
+ENTRY(___fchmodat)
mov ip, r7
ldr r7, =__NR_fchmodat
swi #0
@@ -11,4 +11,5 @@
bxls lr
neg r0, r0
b __set_errno_internal
-END(__fchmodat)
+END(___fchmodat)
+.hidden ___fchmodat
diff --git a/libc/arch-arm64/syscalls/__fchmod.S b/libc/arch-arm64/syscalls/___fchmod.S
similarity index 81%
rename from libc/arch-arm64/syscalls/__fchmod.S
rename to libc/arch-arm64/syscalls/___fchmod.S
index 05c67fc..a143c65 100644
--- a/libc/arch-arm64/syscalls/__fchmod.S
+++ b/libc/arch-arm64/syscalls/___fchmod.S
@@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
-ENTRY(__fchmod)
+ENTRY(___fchmod)
mov x8, __NR_fchmod
svc #0
@@ -11,5 +11,5 @@
b.hi __set_errno_internal
ret
-END(__fchmod)
-.hidden __fchmod
+END(___fchmod)
+.hidden ___fchmod
diff --git a/libc/arch-arm64/syscalls/__fchmodat.S b/libc/arch-arm64/syscalls/___fchmodat.S
similarity index 80%
rename from libc/arch-arm64/syscalls/__fchmodat.S
rename to libc/arch-arm64/syscalls/___fchmodat.S
index 2406ea8..1ab3736 100644
--- a/libc/arch-arm64/syscalls/__fchmodat.S
+++ b/libc/arch-arm64/syscalls/___fchmodat.S
@@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
-ENTRY(__fchmodat)
+ENTRY(___fchmodat)
mov x8, __NR_fchmodat
svc #0
@@ -11,5 +11,5 @@
b.hi __set_errno_internal
ret
-END(__fchmodat)
-.hidden __fchmodat
+END(___fchmodat)
+.hidden ___fchmodat
diff --git a/libc/arch-mips/syscalls/__fchmod.S b/libc/arch-mips/syscalls/___fchmod.S
similarity index 84%
rename from libc/arch-mips/syscalls/__fchmod.S
rename to libc/arch-mips/syscalls/___fchmod.S
index 9bc491c..ac102ec 100644
--- a/libc/arch-mips/syscalls/__fchmod.S
+++ b/libc/arch-mips/syscalls/___fchmod.S
@@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
-ENTRY(__fchmod)
+ENTRY(___fchmod)
.set noreorder
.cpload t9
li v0, __NR_fchmod
@@ -16,4 +16,5 @@
j t9
nop
.set reorder
-END(__fchmod)
+END(___fchmod)
+.hidden ___fchmod
diff --git a/libc/arch-mips/syscalls/__fchmodat.S b/libc/arch-mips/syscalls/___fchmodat.S
similarity index 82%
rename from libc/arch-mips/syscalls/__fchmodat.S
rename to libc/arch-mips/syscalls/___fchmodat.S
index 07ea8f8..d581efa 100644
--- a/libc/arch-mips/syscalls/__fchmodat.S
+++ b/libc/arch-mips/syscalls/___fchmodat.S
@@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
-ENTRY(__fchmodat)
+ENTRY(___fchmodat)
.set noreorder
.cpload t9
li v0, __NR_fchmodat
@@ -16,4 +16,5 @@
j t9
nop
.set reorder
-END(__fchmodat)
+END(___fchmodat)
+.hidden ___fchmodat
diff --git a/libc/arch-mips64/syscalls/__fchmod.S b/libc/arch-mips64/syscalls/___fchmod.S
similarity index 87%
rename from libc/arch-mips64/syscalls/__fchmod.S
rename to libc/arch-mips64/syscalls/___fchmod.S
index 94dd0a1..7c16c54 100644
--- a/libc/arch-mips64/syscalls/__fchmod.S
+++ b/libc/arch-mips64/syscalls/___fchmod.S
@@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
-ENTRY(__fchmod)
+ENTRY(___fchmod)
.set push
.set noreorder
li v0, __NR_fchmod
@@ -22,5 +22,5 @@
j t9
move ra, t0
.set pop
-END(__fchmod)
-.hidden __fchmod
+END(___fchmod)
+.hidden ___fchmod
diff --git a/libc/arch-mips64/syscalls/__fchmodat.S b/libc/arch-mips64/syscalls/___fchmodat.S
similarity index 86%
rename from libc/arch-mips64/syscalls/__fchmodat.S
rename to libc/arch-mips64/syscalls/___fchmodat.S
index 79f453f..50f108e 100644
--- a/libc/arch-mips64/syscalls/__fchmodat.S
+++ b/libc/arch-mips64/syscalls/___fchmodat.S
@@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
-ENTRY(__fchmodat)
+ENTRY(___fchmodat)
.set push
.set noreorder
li v0, __NR_fchmodat
@@ -22,5 +22,5 @@
j t9
move ra, t0
.set pop
-END(__fchmodat)
-.hidden __fchmodat
+END(___fchmodat)
+.hidden ___fchmodat
diff --git a/libc/arch-x86/syscalls/__fchmod.S b/libc/arch-x86/syscalls/___fchmod.S
similarity index 91%
rename from libc/arch-x86/syscalls/__fchmod.S
rename to libc/arch-x86/syscalls/___fchmod.S
index 7ad213e..119a695 100644
--- a/libc/arch-x86/syscalls/__fchmod.S
+++ b/libc/arch-x86/syscalls/___fchmod.S
@@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
-ENTRY(__fchmod)
+ENTRY(___fchmod)
pushl %ebx
.cfi_def_cfa_offset 8
.cfi_rel_offset ebx, 0
@@ -23,4 +23,5 @@
popl %ecx
popl %ebx
ret
-END(__fchmod)
+END(___fchmod)
+.hidden ___fchmod
diff --git a/libc/arch-x86/syscalls/__fchmodat.S b/libc/arch-x86/syscalls/___fchmodat.S
similarity index 91%
rename from libc/arch-x86/syscalls/__fchmodat.S
rename to libc/arch-x86/syscalls/___fchmodat.S
index f03c03f..b15bb64 100644
--- a/libc/arch-x86/syscalls/__fchmodat.S
+++ b/libc/arch-x86/syscalls/___fchmodat.S
@@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
-ENTRY(__fchmodat)
+ENTRY(___fchmodat)
pushl %ebx
.cfi_def_cfa_offset 8
.cfi_rel_offset ebx, 0
@@ -28,4 +28,5 @@
popl %ecx
popl %ebx
ret
-END(__fchmodat)
+END(___fchmodat)
+.hidden ___fchmodat
diff --git a/libc/arch-x86_64/syscalls/__fchmod.S b/libc/arch-x86_64/syscalls/___fchmod.S
similarity index 83%
rename from libc/arch-x86_64/syscalls/__fchmod.S
rename to libc/arch-x86_64/syscalls/___fchmod.S
index ba75f74..7bccbef 100644
--- a/libc/arch-x86_64/syscalls/__fchmod.S
+++ b/libc/arch-x86_64/syscalls/___fchmod.S
@@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
-ENTRY(__fchmod)
+ENTRY(___fchmod)
movl $__NR_fchmod, %eax
syscall
cmpq $-MAX_ERRNO, %rax
@@ -12,5 +12,5 @@
call __set_errno_internal
1:
ret
-END(__fchmod)
-.hidden __fchmod
+END(___fchmod)
+.hidden ___fchmod
diff --git a/libc/arch-x86_64/syscalls/__fchmodat.S b/libc/arch-x86_64/syscalls/___fchmodat.S
similarity index 82%
rename from libc/arch-x86_64/syscalls/__fchmodat.S
rename to libc/arch-x86_64/syscalls/___fchmodat.S
index a8fae95..483ec7d 100644
--- a/libc/arch-x86_64/syscalls/__fchmodat.S
+++ b/libc/arch-x86_64/syscalls/___fchmodat.S
@@ -2,7 +2,7 @@
#include <private/bionic_asm.h>
-ENTRY(__fchmodat)
+ENTRY(___fchmodat)
movl $__NR_fchmodat, %eax
syscall
cmpq $-MAX_ERRNO, %rax
@@ -12,5 +12,5 @@
call __set_errno_internal
1:
ret
-END(__fchmodat)
-.hidden __fchmodat
+END(___fchmodat)
+.hidden ___fchmodat
diff --git a/libc/bionic/fchmod.cpp b/libc/bionic/fchmod.cpp
index 6e020b6..ace8c6b 100644
--- a/libc/bionic/fchmod.cpp
+++ b/libc/bionic/fchmod.cpp
@@ -33,11 +33,11 @@
#include <unistd.h>
#include <stdio.h>
-extern "C" int __fchmod(int, mode_t);
+extern "C" int ___fchmod(int, mode_t);
int fchmod(int fd, mode_t mode) {
int saved_errno = errno;
- int result = __fchmod(fd, mode);
+ int result = ___fchmod(fd, mode);
if ((result == 0) || (errno != EBADF)) {
return result;
diff --git a/libc/bionic/fchmodat.cpp b/libc/bionic/fchmodat.cpp
index c28e15a..1f83c4b 100644
--- a/libc/bionic/fchmodat.cpp
+++ b/libc/bionic/fchmodat.cpp
@@ -34,7 +34,7 @@
#include "private/ErrnoRestorer.h"
-extern "C" int __fchmodat(int, const char*, mode_t);
+extern "C" int ___fchmodat(int, const char*, mode_t);
int fchmodat(int dirfd, const char* pathname, mode_t mode, int flags) {
if ((flags & ~AT_SYMLINK_NOFOLLOW) != 0) {
@@ -63,5 +63,5 @@
return result;
}
- return __fchmodat(dirfd, pathname, mode);
+ return ___fchmodat(dirfd, pathname, mode);
}
diff --git a/libc/tools/gensyscalls.py b/libc/tools/gensyscalls.py
index 4e24077..7e11418d 100755
--- a/libc/tools/gensyscalls.py
+++ b/libc/tools/gensyscalls.py
@@ -286,8 +286,9 @@
for alias in aliases:
stub += function_alias % { "func" : syscall["func"], "alias" : alias }
- # Use hidden visibility for any functions beginning with underscores.
- if pointer_length == 64 and syscall["func"].startswith("__"):
+ # Use hidden visibility on LP64 for any functions beginning with underscores.
+ # Force hidden visibility for any functions which begin with 3 underscores
+ if (pointer_length == 64 and syscall["func"].startswith("__")) or syscall["func"].startswith("___"):
stub += '.hidden ' + syscall["func"] + '\n'
return stub
