diff options
Diffstat (limited to 'system/libffi/pax-dlmmap.patch')
| -rw-r--r-- | system/libffi/pax-dlmmap.patch | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/system/libffi/pax-dlmmap.patch b/system/libffi/pax-dlmmap.patch new file mode 100644 index 000000000..ec4150410 --- /dev/null +++ b/system/libffi/pax-dlmmap.patch @@ -0,0 +1,120 @@ +From 48d2e46528fb6e621d95a7fa194069fd136b712d Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Stefan=20B=C3=BChler?= <buehler@cert.uni-stuttgart.de> +Date: Wed, 7 Sep 2016 15:49:48 +0200 +Subject: [PATCH 1/2] dlmmap_locked always needs locking as it always modifies + execsize + +--- + src/closures.c | 13 ++++--------- + 1 file changed, 4 insertions(+), 9 deletions(-) + +diff --git a/src/closures.c b/src/closures.c +index 2e0ffb45..04d6e27f 100644 +--- a/src/closures.c ++++ b/src/closures.c +@@ -769,16 +769,11 @@ dlmmap (void *start, size_t length, int prot, + MREMAP_DUP and prot at this point. */ + } + +- if (execsize == 0 || execfd == -1) +- { +- pthread_mutex_lock (&open_temp_exec_file_mutex); +- ptr = dlmmap_locked (start, length, prot, flags, offset); +- pthread_mutex_unlock (&open_temp_exec_file_mutex); ++ pthread_mutex_lock (&open_temp_exec_file_mutex); ++ ptr = dlmmap_locked (start, length, prot, flags, offset); ++ pthread_mutex_unlock (&open_temp_exec_file_mutex); + +- return ptr; +- } +- +- return dlmmap_locked (start, length, prot, flags, offset); ++ return ptr; + } + + /* Release memory at the given address, as well as the corresponding + +From 7aad5f895e2dfdb79d2ef67e1b231d21063e6511 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Stefan=20B=C3=BChler?= <buehler@cert.uni-stuttgart.de> +Date: Wed, 7 Sep 2016 15:50:54 +0200 +Subject: [PATCH 2/2] ignore PaX EMUTRAMP flag; instead check for MPROTECT + +- code using ffi_closure_alloc doesn't necessarily generate gcc compatible trampolines; only those are allowed by PaX +- if MPROTECT is enabled use the same workaround as is used for SELinux (double mmap()) +--- + src/closures.c | 29 +++++++++++++---------------- + 1 file changed, 13 insertions(+), 16 deletions(-) + +diff --git a/src/closures.c b/src/closures.c +index 04d6e27f..babecc1a 100644 +--- a/src/closures.c ++++ b/src/closures.c +@@ -401,14 +401,15 @@ selinux_enabled_check (void) + + #endif /* !FFI_MMAP_EXEC_SELINUX */ + +-/* On PaX enable kernels that have MPROTECT enable we can't use PROT_EXEC. */ ++/* On PaX enable kernels that have MPROTECT enabled we can't use PROT_EXEC. */ + #ifdef FFI_MMAP_EXEC_EMUTRAMP_PAX + #include <stdlib.h> + +-static int emutramp_enabled = -1; ++/* -1: not read yet; 0: no PaX or MPROTECT disabled; 1: MPROTECT enabled. */ ++static int mprotect_enabled = -1; + + static int +-emutramp_enabled_check (void) ++mprotect_enabled_check (void) + { + char *buf = NULL; + size_t len = 0; +@@ -422,9 +423,7 @@ emutramp_enabled_check (void) + while (getline (&buf, &len, f) != -1) + if (!strncmp (buf, "PaX:", 4)) + { +- char emutramp; +- if (sscanf (buf, "%*s %*c%c", &emutramp) == 1) +- ret = (emutramp == 'E'); ++ ret = (NULL != strchr (buf + 4, 'M')); + break; + } + free (buf); +@@ -432,8 +431,9 @@ emutramp_enabled_check (void) + return ret; + } + +-#define is_emutramp_enabled() (emutramp_enabled >= 0 ? emutramp_enabled \ +- : (emutramp_enabled = emutramp_enabled_check ())) ++#define is_mprotect_enabled() (mprotect_enabled >= 0 ? mprotect_enabled \ ++ : (mprotect_enabled = mprotect_enabled_check ())) ++ + #endif /* FFI_MMAP_EXEC_EMUTRAMP_PAX */ + + #elif defined (__CYGWIN__) || defined(__INTERIX) +@@ -446,7 +446,7 @@ emutramp_enabled_check (void) + #endif /* !defined(X86_WIN32) && !defined(X86_WIN64) */ + + #ifndef FFI_MMAP_EXEC_EMUTRAMP_PAX +-#define is_emutramp_enabled() 0 ++#define is_mprotect_enabled() 0 + #endif /* FFI_MMAP_EXEC_EMUTRAMP_PAX */ + + /* Declare all functions defined in dlmalloc.c as static. */ +@@ -750,13 +750,10 @@ dlmmap (void *start, size_t length, int prot, + && flags == (MAP_PRIVATE | MAP_ANONYMOUS) + && fd == -1 && offset == 0); + +- if (execfd == -1 && is_emutramp_enabled ()) +- { +- ptr = mmap (start, length, prot & ~PROT_EXEC, flags, fd, offset); +- return ptr; +- } +- +- if (execfd == -1 && !is_selinux_enabled ()) ++ /* -1 != execfd hints that we already decided to use dlmmap_locked ++ last time. If PaX MPROTECT or SELinux is active fallback to ++ dlmmap_locked. */ ++ if (execfd == -1 && !is_mprotect_enabled () && !is_selinux_enabled ()) + { + ptr = mmap (start, length, prot | PROT_EXEC, flags, fd, offset); + |