From f1bcfc796e0a4a04b36284f6261afff59123b1aa Mon Sep 17 00:00:00 2001 From: LiFeng Date: Wed, 16 Jan 2019 05:07:59 -0500 Subject: [PATCH] seccomp: add rules for specified architecture only If the architecture is specified in the seccomp configuration, like: ``` 2 whitelist errno 1 [x86_64] accept allow accept4 allow ``` We shoud add rules only for amd64 instead of add rules for x32/i386/amd64. 1. If the [arch] was not specified in seccomp config, add seccomp rules for all all compat architectures. 2. If the [arch] specified in seccomp config irrelevant to native host arch, the rules will be ignored. 3. If specified [all] in seccomp config, add seccomp rules for all compat architectures. 4. If specified [arch] as same as native host arch, add seccomp rules for the native host arch. 5. If specified [arch] was not native host arch, but compat to host arch, add seccomp rules for the specified arch only, NOT add seccomp rules for native arch. Signed-off-by: LiFeng --- src/lxc/seccomp.c | 185 +++++++++++++++++++++++++++------------------- 1 file changed, 109 insertions(+), 76 deletions(-) diff --git a/src/lxc/seccomp.c b/src/lxc/seccomp.c index f90602e1f..8f80e4049 100644 --- a/src/lxc/seccomp.c +++ b/src/lxc/seccomp.c @@ -291,7 +291,7 @@ on_error: #endif #if HAVE_DECL_SECCOMP_SYSCALL_RESOLVE_NAME_ARCH -enum lxc_hostarch_t { +enum lxc_arch_t { lxc_seccomp_arch_all = 0, lxc_seccomp_arch_native, lxc_seccomp_arch_i386, @@ -345,8 +345,8 @@ int get_hostarch(void) return lxc_seccomp_arch_unknown; } -scmp_filter_ctx get_new_ctx(enum lxc_hostarch_t n_arch, - uint32_t default_policy_action, bool *needs_merge) +scmp_filter_ctx get_new_ctx(enum lxc_arch_t n_arch, + uint32_t default_policy_action) { int ret; uint32_t arch; @@ -464,10 +464,7 @@ scmp_filter_ctx get_new_ctx(enum lxc_hostarch_t n_arch, return NULL; } TRACE("Removed native arch from main seccomp context"); - - *needs_merge = true; } else { - *needs_merge = false; TRACE("Arch %d already present in main seccomp context", (int)n_arch); } @@ -550,6 +547,27 @@ bool do_resolve_add_rule(uint32_t arch, char *line, scmp_filter_ctx ctx, return true; } +#define SCMP_ARCH_INDEX_MAX 3 + +struct scmp_ctx_info { + uint32_t architectures[SCMP_ARCH_INDEX_MAX]; + enum lxc_arch_t lxc_arch[SCMP_ARCH_INDEX_MAX]; + scmp_filter_ctx contexts[SCMP_ARCH_INDEX_MAX]; + bool needs_merge[SCMP_ARCH_INDEX_MAX]; +}; + +static int get_arch_index(enum lxc_arch_t arch, struct scmp_ctx_info *ctx) +{ + int i; + + for (i = 0; i < SCMP_ARCH_INDEX_MAX; i++) { + if (ctx->lxc_arch[i] == arch) + return i; + } + + return -1; +} + /* * v2 consists of * [x86] @@ -568,15 +586,11 @@ static int parse_config_v2(FILE *f, char *line, size_t *line_bufsz, struct lxc_c { int ret; char *p; - enum lxc_hostarch_t cur_rule_arch, native_arch; + enum lxc_arch_t cur_rule_arch, native_arch; bool blacklist = false; uint32_t default_policy_action = -1, default_rule_action = -1; struct seccomp_v2_rule rule; - struct scmp_ctx_info { - uint32_t architectures[3]; - scmp_filter_ctx contexts[3]; - bool needs_merge[3]; - } ctx; + struct scmp_ctx_info ctx; if (strncmp(line, "blacklist", 9) == 0) blacklist = true; @@ -617,23 +631,23 @@ static int parse_config_v2(FILE *f, char *line, size_t *line_bufsz, struct lxc_c cur_rule_arch = lxc_seccomp_arch_all; ctx.architectures[0] = SCMP_ARCH_X86; + ctx.lxc_arch[0] = lxc_seccomp_arch_i386; ctx.contexts[0] = get_new_ctx(lxc_seccomp_arch_i386, - default_policy_action, - &ctx.needs_merge[0]); + default_policy_action); if (!ctx.contexts[0]) goto bad; ctx.architectures[1] = SCMP_ARCH_X32; + ctx.lxc_arch[1] = lxc_seccomp_arch_x32; ctx.contexts[1] = get_new_ctx(lxc_seccomp_arch_x32, - default_policy_action, - &ctx.needs_merge[1]); + default_policy_action); if (!ctx.contexts[1]) goto bad; ctx.architectures[2] = SCMP_ARCH_X86_64; + ctx.lxc_arch[2] = lxc_seccomp_arch_amd64; ctx.contexts[2] = get_new_ctx(lxc_seccomp_arch_amd64, - default_policy_action, - &ctx.needs_merge[2]); + default_policy_action); if (!ctx.contexts[2]) goto bad; #ifdef SCMP_ARCH_PPC @@ -641,17 +655,17 @@ static int parse_config_v2(FILE *f, char *line, size_t *line_bufsz, struct lxc_c cur_rule_arch = lxc_seccomp_arch_all; ctx.architectures[0] = SCMP_ARCH_PPC; + ctx.lxc_arch[0] = lxc_seccomp_arch_ppc; ctx.contexts[0] = get_new_ctx(lxc_seccomp_arch_ppc, - default_policy_action, - &ctx.needs_merge[0]); + default_policy_action); if (!ctx.contexts[0]) goto bad; - ctx.architectures[2] = SCMP_ARCH_PPC64; - ctx.contexts[2] = get_new_ctx(lxc_seccomp_arch_ppc64, - default_policy_action, - &ctx.needs_merge[2]); - if (!ctx.contexts[2]) + ctx.architectures[1] = SCMP_ARCH_PPC64; + ctx.lxc_arch[1] = lxc_seccomp_arch_ppc64; + ctx.contexts[1] = get_new_ctx(lxc_seccomp_arch_ppc64, + default_policy_action); + if (!ctx.contexts[1]) goto bad; #endif #ifdef SCMP_ARCH_ARM @@ -659,18 +673,18 @@ static int parse_config_v2(FILE *f, char *line, size_t *line_bufsz, struct lxc_c cur_rule_arch = lxc_seccomp_arch_all; ctx.architectures[0] = SCMP_ARCH_ARM; + ctx.lxc_arch[0] = lxc_seccomp_arch_arm; ctx.contexts[0] = get_new_ctx(lxc_seccomp_arch_arm, - default_policy_action, - &ctx.needs_merge[0]); + default_policy_action); if (!ctx.contexts[0]) goto bad; #ifdef SCMP_ARCH_AARCH64 - ctx.architectures[2] = SCMP_ARCH_AARCH64; - ctx.contexts[2] = get_new_ctx(lxc_seccomp_arch_arm64, - default_policy_action, - &ctx.needs_merge[2]); - if (!ctx.contexts[2]) + ctx.architectures[1] = SCMP_ARCH_AARCH64; + ctx.lxc_arch[1] = lxc_seccomp_arch_arm64; + ctx.contexts[1] = get_new_ctx(lxc_seccomp_arch_arm64, + default_policy_action); + if (!ctx.contexts[1]) goto bad; #endif #endif @@ -679,46 +693,46 @@ static int parse_config_v2(FILE *f, char *line, size_t *line_bufsz, struct lxc_c cur_rule_arch = lxc_seccomp_arch_all; ctx.architectures[0] = SCMP_ARCH_MIPS; + ctx.lxc_arch[0] = lxc_seccomp_arch_mips; ctx.contexts[0] = get_new_ctx(lxc_seccomp_arch_mips, - default_policy_action, - &ctx.needs_merge[0]); + default_policy_action); if (!ctx.contexts[0]) goto bad; ctx.architectures[1] = SCMP_ARCH_MIPS64N32; + ctx.lxc_arch[1] = lxc_seccomp_arch_mips64n32; ctx.contexts[1] = get_new_ctx(lxc_seccomp_arch_mips64n32, - default_policy_action, - &ctx.needs_merge[1]); + default_policy_action); if (!ctx.contexts[1]) goto bad; ctx.architectures[2] = SCMP_ARCH_MIPS64; + ctx.lxc_arch[2] = lxc_seccomp_arch_mips64; ctx.contexts[2] = get_new_ctx(lxc_seccomp_arch_mips64, - default_policy_action, - &ctx.needs_merge[2]); + default_policy_action); if (!ctx.contexts[2]) goto bad; } else if (native_arch == lxc_seccomp_arch_mipsel64) { cur_rule_arch = lxc_seccomp_arch_all; ctx.architectures[0] = SCMP_ARCH_MIPSEL; + ctx.lxc_arch[0] = lxc_seccomp_arch_mipsel; ctx.contexts[0] = get_new_ctx(lxc_seccomp_arch_mipsel, - default_policy_action, - &ctx.needs_merge[0]); + default_policy_action); if (!ctx.contexts[0]) goto bad; ctx.architectures[1] = SCMP_ARCH_MIPSEL64N32; + ctx.lxc_arch[1] = lxc_seccomp_arch_mipsel64n32; ctx.contexts[1] = get_new_ctx(lxc_seccomp_arch_mipsel64n32, - default_policy_action, - &ctx.needs_merge[1]); + default_policy_action); if (!ctx.contexts[1]) goto bad; ctx.architectures[2] = SCMP_ARCH_MIPSEL64; + ctx.lxc_arch[2] = lxc_seccomp_arch_mipsel64; ctx.contexts[2] = get_new_ctx(lxc_seccomp_arch_mipsel64, - default_policy_action, - &ctx.needs_merge[2]); + default_policy_action); if (!ctx.contexts[2]) goto bad; #endif @@ -928,43 +942,62 @@ static int parse_config_v2(FILE *f, char *line, size_t *line_bufsz, struct lxc_c goto bad_rule; } - if (!do_resolve_add_rule(SCMP_ARCH_NATIVE, line, - conf->seccomp_ctx, &rule)) - goto bad_rule; - - INFO("Added native rule for arch %d for %s action %d(%s)", - SCMP_ARCH_NATIVE, line, rule.action, - get_action_name(rule.action)); - - if (ctx.architectures[0] != SCMP_ARCH_NATIVE) { - if (!do_resolve_add_rule(ctx.architectures[0], line, - ctx.contexts[0], &rule)) + if (cur_rule_arch == native_arch) { + if (!do_resolve_add_rule(SCMP_ARCH_NATIVE, line, + conf->seccomp_ctx, &rule)) goto bad_rule; - INFO("Added compat rule for arch %d for %s action %d(%s)", - ctx.architectures[0], line, rule.action, + INFO("Added native rule for arch %d for %s action %d(%s)", + SCMP_ARCH_NATIVE, line, rule.action, get_action_name(rule.action)); - } + } else if (cur_rule_arch != lxc_seccomp_arch_all) { + int arch_index = get_arch_index(cur_rule_arch, &ctx); + if (arch_index < 0) + goto bad_arch; - if (ctx.architectures[1] != SCMP_ARCH_NATIVE) { - if (!do_resolve_add_rule(ctx.architectures[1], line, - ctx.contexts[1], &rule)) + if (!do_resolve_add_rule(ctx.architectures[arch_index], line, + ctx.contexts[arch_index], &rule)) goto bad_rule; INFO("Added compat rule for arch %d for %s action %d(%s)", - ctx.architectures[1], line, rule.action, + ctx.architectures[arch_index], line, rule.action, get_action_name(rule.action)); - } + ctx.needs_merge[arch_index] = true; + } else { + if (ctx.architectures[0] != SCMP_ARCH_NATIVE) { + if (!do_resolve_add_rule(ctx.architectures[0], line, + ctx.contexts[0], &rule)) + goto bad_rule; + + INFO("Added compat rule for arch %d for %s action %d(%s)", + ctx.architectures[0], line, rule.action, + get_action_name(rule.action)); + ctx.needs_merge[0] = true; + } - if (ctx.architectures[2] != SCMP_ARCH_NATIVE) { - if (!do_resolve_add_rule(ctx.architectures[2], line, - ctx.contexts[2], &rule)) - goto bad_rule; + if (ctx.architectures[1] != SCMP_ARCH_NATIVE) { + if (!do_resolve_add_rule(ctx.architectures[1], line, + ctx.contexts[1], &rule)) + goto bad_rule; - INFO("Added native rule for arch %d for %s action %d(%s)", - ctx.architectures[2], line, rule.action, - get_action_name(rule.action)); + INFO("Added compat rule for arch %d for %s action %d(%s)", + ctx.architectures[1], line, rule.action, + get_action_name(rule.action)); + ctx.needs_merge[1] = true; + } + + if (ctx.architectures[2] != SCMP_ARCH_NATIVE) { + if (!do_resolve_add_rule(ctx.architectures[2], line, + ctx.contexts[2], &rule)) + goto bad_rule; + + INFO("Added native rule for arch %d for %s action %d(%s)", + ctx.architectures[2], line, rule.action, + get_action_name(rule.action)); + ctx.needs_merge[2] = true; + } } + } INFO("Merging compat seccomp contexts into main context"); @@ -972,8 +1005,8 @@ static int parse_config_v2(FILE *f, char *line, size_t *line_bufsz, struct lxc_c if (ctx.needs_merge[0]) { ret = seccomp_merge(conf->seccomp_ctx, ctx.contexts[0]); if (ret < 0) { - ERROR("Failed to merge first compat seccomp " - "context into main context"); + ERROR("%s - Failed to merge first compat seccomp " + "context into main context", strerror(-ret)); goto bad; } @@ -988,8 +1021,8 @@ static int parse_config_v2(FILE *f, char *line, size_t *line_bufsz, struct lxc_c if (ctx.needs_merge[1]) { ret = seccomp_merge(conf->seccomp_ctx, ctx.contexts[1]); if (ret < 0) { - ERROR("Failed to merge first compat seccomp " - "context into main context"); + ERROR("%s - Failed to merge second compat seccomp " + "context into main context", strerror(-ret)); goto bad; } @@ -1004,8 +1037,8 @@ static int parse_config_v2(FILE *f, char *line, size_t *line_bufsz, struct lxc_c if (ctx.needs_merge[2]) { ret = seccomp_merge(conf->seccomp_ctx, ctx.contexts[2]); if (ret < 0) { - ERROR("Failed to merge third compat seccomp " - "context into main context"); + ERROR("%s - Failed to merge third compat seccomp " + "context into main context", strerror(-ret)); goto bad; } -- 2.47.2