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-rw-r--r--net-vpn/tor/files/tor-0.4.7.16-arm64-sandbox.patch337
1 files changed, 337 insertions, 0 deletions
diff --git a/net-vpn/tor/files/tor-0.4.7.16-arm64-sandbox.patch b/net-vpn/tor/files/tor-0.4.7.16-arm64-sandbox.patch
new file mode 100644
index 000000000000..2b473bf981b6
--- /dev/null
+++ b/net-vpn/tor/files/tor-0.4.7.16-arm64-sandbox.patch
@@ -0,0 +1,337 @@
+From https://gitlab.torproject.org/tpo/core/tor/-/merge_requests/574
+Gentoo Bug: https://bugs.gentoo.org/920063
+From: Pierre Bourdon <delroth@gmail.com>
+Date: Sat, 30 Apr 2022 11:52:59 +0200
+Subject: [PATCH 1/4] sandbox: fix openat filtering on AArch64
+
+New glibc versions not sign-extending 32 bit negative constants seems to
+not be a thing on AArch64. I suspect that this might not be the only
+architecture where the sign-extensions is happening, and the correct fix
+might be instead to use a proper 32 bit comparison for the first openat
+parameter. For now, band-aid fix this so the sandbox can work again on
+AArch64.
+--- a/src/lib/sandbox/sandbox.c
++++ b/src/lib/sandbox/sandbox.c
+@@ -518,7 +518,12 @@ libc_uses_openat_for_opendir(void)
+ static int
+ libc_negative_constant_needs_cast(void)
+ {
++#if defined(__aarch64__) && defined(__LP64__)
++ /* Existing glibc versions always sign-extend to 64 bits on AArch64. */
++ return 0;
++#else
+ return is_libc_at_least(2, 27);
++#endif
+ }
+
+ /** Allow a single file to be opened. If <b>use_openat</b> is true,
+--
+GitLab
+
+
+From 8fd13f7a7bfd4efc02d888ce9d10bcb6a80a03c8 Mon Sep 17 00:00:00 2001
+From: Pierre Bourdon <delroth@gmail.com>
+Date: Sat, 30 Apr 2022 13:02:16 +0200
+Subject: [PATCH 2/4] sandbox: filter {chown,chmod,rename} via their *at
+ variant on Aarch64
+
+The chown/chmod/rename syscalls have never existed on AArch64, and libc
+implements the POSIX functions via the fchownat/fchmodat/renameat
+syscalls instead.
+
+Add new filter functions for fchownat/fchmodat/renameat, not made
+architecture specific since the syscalls exists everywhere else too.
+However, in order to limit seccomp filter space usage, we only insert
+rules for one of {chown, chown32, fchownat} depending on the
+architecture (resp. {chmod, fchmodat}, {rename, renameat}).
+--- a/src/lib/sandbox/sandbox.c
++++ b/src/lib/sandbox/sandbox.c
+@@ -614,6 +614,32 @@ sb_chmod(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
+ return 0;
+ }
+
++static int
++sb_fchmodat(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
++{
++ int rc;
++ sandbox_cfg_t *elem = NULL;
++
++ // for each dynamic parameter filters
++ for (elem = filter; elem != NULL; elem = elem->next) {
++ smp_param_t *param = elem->param;
++
++ if (param != NULL && param->prot == 1 && param->syscall
++ == SCMP_SYS(fchmodat)) {
++ rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(fchmodat),
++ SCMP_CMP_NEG(0, SCMP_CMP_EQ, AT_FDCWD),
++ SCMP_CMP_STR(1, SCMP_CMP_EQ, param->value));
++ if (rc != 0) {
++ log_err(LD_BUG,"(Sandbox) failed to add fchmodat syscall, received "
++ "libseccomp error %d", rc);
++ return rc;
++ }
++ }
++ }
++
++ return 0;
++}
++
+ #ifdef __i386__
+ static int
+ sb_chown32(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
+@@ -666,6 +692,32 @@ sb_chown(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
+ }
+ #endif /* defined(__i386__) */
+
++static int
++sb_fchownat(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
++{
++ int rc;
++ sandbox_cfg_t *elem = NULL;
++
++ // for each dynamic parameter filters
++ for (elem = filter; elem != NULL; elem = elem->next) {
++ smp_param_t *param = elem->param;
++
++ if (param != NULL && param->prot == 1 && param->syscall
++ == SCMP_SYS(fchownat)) {
++ rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(fchownat),
++ SCMP_CMP_NEG(0, SCMP_CMP_EQ, AT_FDCWD),
++ SCMP_CMP_STR(1, SCMP_CMP_EQ, param->value));
++ if (rc != 0) {
++ log_err(LD_BUG,"(Sandbox) failed to add fchownat syscall, received "
++ "libseccomp error %d", rc);
++ return rc;
++ }
++ }
++ }
++
++ return 0;
++}
++
+ /**
+ * Function responsible for setting up the rename syscall for
+ * the seccomp filter sandbox.
+@@ -697,6 +749,39 @@ sb_rename(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
+ return 0;
+ }
+
++/**
++ * Function responsible for setting up the renameat syscall for
++ * the seccomp filter sandbox.
++ */
++static int
++sb_renameat(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
++{
++ int rc;
++ sandbox_cfg_t *elem = NULL;
++
++ // for each dynamic parameter filters
++ for (elem = filter; elem != NULL; elem = elem->next) {
++ smp_param_t *param = elem->param;
++
++ if (param != NULL && param->prot == 1 &&
++ param->syscall == SCMP_SYS(renameat)) {
++
++ rc = seccomp_rule_add_4(ctx, SCMP_ACT_ALLOW, SCMP_SYS(renameat),
++ SCMP_CMP_NEG(0, SCMP_CMP_EQ, AT_FDCWD),
++ SCMP_CMP_STR(1, SCMP_CMP_EQ, param->value),
++ SCMP_CMP_NEG(2, SCMP_CMP_EQ, AT_FDCWD),
++ SCMP_CMP_STR(3, SCMP_CMP_EQ, param->value2));
++ if (rc != 0) {
++ log_err(LD_BUG,"(Sandbox) failed to add renameat syscall, received "
++ "libseccomp error %d", rc);
++ return rc;
++ }
++ }
++ }
++
++ return 0;
++}
++
+ /**
+ * Function responsible for setting up the openat syscall for
+ * the seccomp filter sandbox.
+@@ -1317,7 +1402,9 @@ static sandbox_filter_func_t filter_func[] = {
+ #else
+ sb_chown,
+ #endif
++ sb_fchownat,
+ sb_chmod,
++ sb_fchmodat,
+ sb_open,
+ sb_openat,
+ sb_opendir,
+@@ -1325,6 +1412,7 @@ static sandbox_filter_func_t filter_func[] = {
+ sb_ptrace,
+ #endif
+ sb_rename,
++ sb_renameat,
+ #ifdef __NR_fcntl64
+ sb_fcntl64,
+ #endif
+@@ -1592,10 +1680,24 @@ new_element(int syscall, char *value)
+
+ #ifdef __i386__
+ #define SCMP_chown SCMP_SYS(chown32)
++#elif defined(__aarch64__) && defined(__LP64__)
++#define SCMP_chown SCMP_SYS(fchownat)
+ #else
+ #define SCMP_chown SCMP_SYS(chown)
+ #endif
+
++#if defined(__aarch64__) && defined(__LP64__)
++#define SCMP_chmod SCMP_SYS(fchmodat)
++#else
++#define SCMP_chmod SCMP_SYS(chmod)
++#endif
++
++#if defined(__aarch64__) && defined(__LP64__)
++#define SCMP_rename SCMP_SYS(renameat)
++#else
++#define SCMP_rename SCMP_SYS(rename)
++#endif
++
+ #ifdef __NR_stat64
+ #define SCMP_stat SCMP_SYS(stat64)
+ #else
+@@ -1633,7 +1735,7 @@ sandbox_cfg_allow_chmod_filename(sandbox_cfg_t **cfg, char *file)
+ {
+ sandbox_cfg_t *elem = NULL;
+
+- elem = new_element(SCMP_SYS(chmod), file);
++ elem = new_element(SCMP_chmod, file);
+
+ elem->next = *cfg;
+ *cfg = elem;
+@@ -1659,7 +1761,7 @@ sandbox_cfg_allow_rename(sandbox_cfg_t **cfg, char *file1, char *file2)
+ {
+ sandbox_cfg_t *elem = NULL;
+
+- elem = new_element2(SCMP_SYS(rename), file1, file2);
++ elem = new_element2(SCMP_rename, file1, file2);
+
+ elem->next = *cfg;
+ *cfg = elem;
+--
+GitLab
+
+
+From eb0749d64917fee6ff74c3810dbec8cd063f546c Mon Sep 17 00:00:00 2001
+From: Pierre Bourdon <delroth@gmail.com>
+Date: Wed, 4 May 2022 07:19:40 +0200
+Subject: [PATCH 3/4] sandbox: replace SCMP_CMP_NEG with masked equality checks
+
+For some syscalls the kernel ABI uses 32 bit signed integers. Whether
+these 32 bit integer values are sign extended or zero extended to the
+native 64 bit register sizes is undefined and dependent on the {arch,
+compiler, libc} being used. Instead of trying to detect which cases
+zero-extend and which cases sign-extend, this commit uses a masked
+equality check on the lower 32 bits of the value.
+--- a/src/lib/sandbox/sandbox.c
++++ b/src/lib/sandbox/sandbox.c
+@@ -141,10 +141,12 @@ static sandbox_cfg_t *filter_dynamic = NULL;
+ * the high bits of the value might get masked out improperly. */
+ #define SCMP_CMP_MASKED(a,b,c) \
+ SCMP_CMP4((a), SCMP_CMP_MASKED_EQ, ~(scmp_datum_t)(b), (c))
+-/* For negative constants, the rule to add depends on the glibc version. */
+-#define SCMP_CMP_NEG(a,op,b) (libc_negative_constant_needs_cast() ? \
+- (SCMP_CMP((a), (op), (unsigned int)(b))) : \
+- (SCMP_CMP_STR((a), (op), (b))))
++/* Negative constants aren't consistently sign extended or zero extended.
++ * Different compilers, libc, and architectures behave differently. For cases
++ * where the kernel ABI uses a 32 bit integer, this macro can be used to
++ * mask-compare only the lower 32 bits of the value. */
++#define SCMP_CMP_LOWER32_EQ(a,b) \
++ SCMP_CMP4((a), SCMP_CMP_MASKED_EQ, 0xFFFFFFFF, (unsigned int)(b))
+
+ /** Variable used for storing all syscall numbers that will be allowed with the
+ * stage 1 general Tor sandbox.
+@@ -513,19 +515,6 @@ libc_uses_openat_for_opendir(void)
+ (is_libc_at_least(2, 15) && !is_libc_at_least(2, 22));
+ }
+
+-/* Return true if we think we're running with a libc that needs to cast
+- * negative arguments like AT_FDCWD for seccomp rules. */
+-static int
+-libc_negative_constant_needs_cast(void)
+-{
+-#if defined(__aarch64__) && defined(__LP64__)
+- /* Existing glibc versions always sign-extend to 64 bits on AArch64. */
+- return 0;
+-#else
+- return is_libc_at_least(2, 27);
+-#endif
+-}
+-
+ /** Allow a single file to be opened. If <b>use_openat</b> is true,
+ * we're using a libc that remaps all the opens into openats. */
+ static int
+@@ -533,7 +522,7 @@ allow_file_open(scmp_filter_ctx ctx, int use_openat, const char *file)
+ {
+ if (use_openat) {
+ return seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(openat),
+- SCMP_CMP_NEG(0, SCMP_CMP_EQ, AT_FDCWD),
++ SCMP_CMP_LOWER32_EQ(0, AT_FDCWD),
+ SCMP_CMP_STR(1, SCMP_CMP_EQ, file));
+ } else {
+ return seccomp_rule_add_1(ctx, SCMP_ACT_ALLOW, SCMP_SYS(open),
+@@ -627,7 +616,7 @@ sb_fchmodat(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
+ if (param != NULL && param->prot == 1 && param->syscall
+ == SCMP_SYS(fchmodat)) {
+ rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(fchmodat),
+- SCMP_CMP_NEG(0, SCMP_CMP_EQ, AT_FDCWD),
++ SCMP_CMP_LOWER32_EQ(0, AT_FDCWD),
+ SCMP_CMP_STR(1, SCMP_CMP_EQ, param->value));
+ if (rc != 0) {
+ log_err(LD_BUG,"(Sandbox) failed to add fchmodat syscall, received "
+@@ -705,7 +694,7 @@ sb_fchownat(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
+ if (param != NULL && param->prot == 1 && param->syscall
+ == SCMP_SYS(fchownat)) {
+ rc = seccomp_rule_add_2(ctx, SCMP_ACT_ALLOW, SCMP_SYS(fchownat),
+- SCMP_CMP_NEG(0, SCMP_CMP_EQ, AT_FDCWD),
++ SCMP_CMP_LOWER32_EQ(0, AT_FDCWD),
+ SCMP_CMP_STR(1, SCMP_CMP_EQ, param->value));
+ if (rc != 0) {
+ log_err(LD_BUG,"(Sandbox) failed to add fchownat syscall, received "
+@@ -767,9 +756,9 @@ sb_renameat(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
+ param->syscall == SCMP_SYS(renameat)) {
+
+ rc = seccomp_rule_add_4(ctx, SCMP_ACT_ALLOW, SCMP_SYS(renameat),
+- SCMP_CMP_NEG(0, SCMP_CMP_EQ, AT_FDCWD),
++ SCMP_CMP_LOWER32_EQ(0, AT_FDCWD),
+ SCMP_CMP_STR(1, SCMP_CMP_EQ, param->value),
+- SCMP_CMP_NEG(2, SCMP_CMP_EQ, AT_FDCWD),
++ SCMP_CMP_LOWER32_EQ(2, AT_FDCWD),
+ SCMP_CMP_STR(3, SCMP_CMP_EQ, param->value2));
+ if (rc != 0) {
+ log_err(LD_BUG,"(Sandbox) failed to add renameat syscall, received "
+@@ -799,7 +788,7 @@ sb_openat(scmp_filter_ctx ctx, sandbox_cfg_t *filter)
+ if (param != NULL && param->prot == 1 && param->syscall
+ == SCMP_SYS(openat)) {
+ rc = seccomp_rule_add_3(ctx, SCMP_ACT_ALLOW, SCMP_SYS(openat),
+- SCMP_CMP_NEG(0, SCMP_CMP_EQ, AT_FDCWD),
++ SCMP_CMP_LOWER32_EQ(0, AT_FDCWD),
+ SCMP_CMP_STR(1, SCMP_CMP_EQ, param->value),
+ SCMP_CMP(2, SCMP_CMP_EQ, O_RDONLY|O_NONBLOCK|O_LARGEFILE|O_DIRECTORY|
+ O_CLOEXEC));
+--
+GitLab
+
+
+From 42034ae9da2866c67ce8cb8522d6a619d8b21170 Mon Sep 17 00:00:00 2001
+From: Pierre Bourdon <delroth@gmail.com>
+Date: Wed, 4 May 2022 07:31:06 +0200
+Subject: [PATCH 4/4] changes: add entry for MR !574
+
+--- /dev/null
++++ b/changes/aarch64_sandbox
+@@ -0,0 +1,5 @@
++ o Minor bugfixes (sandbox):
++ - Fix sandbox support on AArch64 systems. More "*at" variants of syscalls
++ are now supported. Signed 32 bit syscall parameters are checked more
++ precisely, which should lead to lower likelihood of breakages with future
++ compiler and libc releases. Fixes bug 40599; bugfix on 0.4.4.3-alpha.
+--
+GitLab
+
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