From b4357a8eb6b9a5c0452fc0d127e37e54dc09e1a0 Mon Sep 17 00:00:00 2001 From: Jerzi Kaminsky Date: Sat, 15 Apr 2017 17:04:04 +0300 Subject: Rename get_policy to get_feature_policy --- sway/commands/permit.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'sway/commands/permit.c') diff --git a/sway/commands/permit.c b/sway/commands/permit.c index e2bec2e2..4a78ef0d 100644 --- a/sway/commands/permit.c +++ b/sway/commands/permit.c @@ -38,7 +38,7 @@ static enum secure_feature get_features(int argc, char **argv, return features; } -static struct feature_policy *get_policy(const char *name) { +static struct feature_policy *get_feature_policy(const char *name) { struct feature_policy *policy = NULL; for (int i = 0; i < config->feature_policies->length; ++i) { struct feature_policy *p = config->feature_policies->items[i]; @@ -66,7 +66,7 @@ struct cmd_results *cmd_permit(int argc, char **argv) { return error; } - struct feature_policy *policy = get_policy(argv[0]); + struct feature_policy *policy = get_feature_policy(argv[0]); policy->features |= get_features(argc, argv, &error); sway_log(L_DEBUG, "Permissions granted to %s for features %d", @@ -84,7 +84,7 @@ struct cmd_results *cmd_reject(int argc, char **argv) { return error; } - struct feature_policy *policy = get_policy(argv[0]); + struct feature_policy *policy = get_feature_policy(argv[0]); policy->features &= ~get_features(argc, argv, &error); sway_log(L_DEBUG, "Permissions granted to %s for features %d", -- cgit v1.2.3 From bfb99235e323e31689e280867103d3bc2e39ac22 Mon Sep 17 00:00:00 2001 From: Jerzi Kaminsky Date: Sat, 15 Apr 2017 17:16:32 +0300 Subject: Move get_feature_policy to sway/security.c --- include/sway/security.h | 2 ++ sway/commands/permit.c | 19 ------------------- sway/security.c | 20 ++++++++++++++++++++ 3 files changed, 22 insertions(+), 19 deletions(-) (limited to 'sway/commands/permit.c') diff --git a/include/sway/security.h b/include/sway/security.h index d60f264a..0edffdfa 100644 --- a/include/sway/security.h +++ b/include/sway/security.h @@ -7,6 +7,8 @@ uint32_t get_feature_policy_mask(pid_t pid); uint32_t get_ipc_policy_mask(pid_t pid); uint32_t get_command_policy_mask(const char *cmd); +struct feature_policy *get_feature_policy(const char *name); + const char *command_policy_str(enum command_context context); struct feature_policy *alloc_feature_policy(const char *program); diff --git a/sway/commands/permit.c b/sway/commands/permit.c index 4a78ef0d..c55f46d8 100644 --- a/sway/commands/permit.c +++ b/sway/commands/permit.c @@ -38,25 +38,6 @@ static enum secure_feature get_features(int argc, char **argv, return features; } -static struct feature_policy *get_feature_policy(const char *name) { - struct feature_policy *policy = NULL; - for (int i = 0; i < config->feature_policies->length; ++i) { - struct feature_policy *p = config->feature_policies->items[i]; - if (strcmp(p->program, name) == 0) { - policy = p; - break; - } - } - if (!policy) { - policy = alloc_feature_policy(name); - if (!policy) { - sway_abort("Unable to allocate security policy"); - } - list_add(config->feature_policies, policy); - } - return policy; -} - struct cmd_results *cmd_permit(int argc, char **argv) { struct cmd_results *error = NULL; if ((error = checkarg(argc, "permit", EXPECTED_MORE_THAN, 1))) { diff --git a/sway/security.c b/sway/security.c index 5b762b07..96af2b88 100644 --- a/sway/security.c +++ b/sway/security.c @@ -94,6 +94,26 @@ static const char *get_pid_exe(pid_t pid) { return link; } +struct feature_policy *get_feature_policy(const char *name) { + struct feature_policy *policy = NULL; + + for (int i = 0; i < config->feature_policies->length; ++i) { + struct feature_policy *p = config->feature_policies->items[i]; + if (strcmp(p->program, name) == 0) { + policy = p; + break; + } + } + if (!policy) { + policy = alloc_feature_policy(name); + if (!policy) { + sway_abort("Unable to allocate security policy"); + } + list_add(config->feature_policies, policy); + } + return policy; +} + uint32_t get_feature_policy_mask(pid_t pid) { uint32_t default_policy = 0; const char *link = get_pid_exe(pid); -- cgit v1.2.3 From 2ad8850398693cb572152e6d97c59de371996273 Mon Sep 17 00:00:00 2001 From: Jerzi Kaminsky Date: Sun, 16 Apr 2017 09:30:14 +0300 Subject: Handle symlinks as IPC security targets - When policies are allocated, the ipc target path goes through symlink resolution. The result is used as the canonical for matching pids to policies at runtime. In particular, this matches up with the target of the `/proc//exe`. - There's a possible race condition if this isn't done correctly, read below. Originally, validate_ipc_target() always tried to resolve its argument for symlinks, and returned a parogram target string if it validates. This created a possible race condition with security implications. The problem is that get_feature_policy() first independently resolved the policy target in order to check whether a policy already exists. If it didn't find any, it called alloc_feature_policy() which called validate_ipc_target() which resolved the policy target again. In the time between the two checks, the symlink could be altered, and a lucky attacker could fool the program into thinking that a policy doesn't exist for a target, and then switch the symlink to point at another file. At the very least this could allow him to create two policies for the same program target, and possibly to bypass security by associating the permissions for one target with another, or force default permissions to apply to a target for which a more specific rule has been configured. So we don't that. Instead, the policy target is resolved once and that result is used for the rest of the lookup/creation process. --- sway/commands/ipc.c | 10 +++++++++- sway/commands/permit.c | 39 ++++++++++++++++++++++++++++++++++++--- 2 files changed, 45 insertions(+), 4 deletions(-) (limited to 'sway/commands/permit.c') diff --git a/sway/commands/ipc.c b/sway/commands/ipc.c index 8a7b849f..f0b3035a 100644 --- a/sway/commands/ipc.c +++ b/sway/commands/ipc.c @@ -1,3 +1,4 @@ +#define _XOPEN_SOURCE 500 #include #include #include "sway/security.h" @@ -18,8 +19,14 @@ struct cmd_results *cmd_ipc(int argc, char **argv) { return error; } - const char *program = argv[0]; + char *program = NULL; + if (!strcmp(argv[0], "*")) { + program = strdup(argv[0]); + } else if (!(program = resolve_path(argv[0]))) { + return cmd_results_new( + CMD_INVALID, "ipc", "Unable to resolve IPC Policy target."); + } if (config->reading && strcmp("{", argv[1]) != 0) { return cmd_results_new(CMD_INVALID, "ipc", "Expected '{' at start of IPC config definition."); @@ -32,6 +39,7 @@ struct cmd_results *cmd_ipc(int argc, char **argv) { current_policy = alloc_ipc_policy(program); list_add(config->ipc_policies, current_policy); + free(program); return cmd_results_new(CMD_BLOCK_IPC, NULL, NULL); } diff --git a/sway/commands/permit.c b/sway/commands/permit.c index c55f46d8..66fa4e2a 100644 --- a/sway/commands/permit.c +++ b/sway/commands/permit.c @@ -1,7 +1,9 @@ +#define _XOPEN_SOURCE 500 #include #include "sway/commands.h" #include "sway/config.h" #include "sway/security.h" +#include "util.h" #include "log.h" static enum secure_feature get_features(int argc, char **argv, @@ -47,12 +49,29 @@ struct cmd_results *cmd_permit(int argc, char **argv) { return error; } - struct feature_policy *policy = get_feature_policy(argv[0]); - policy->features |= get_features(argc, argv, &error); + bool assign_perms = true; + char *program = NULL; + if (!strcmp(argv[0], "*")) { + program = strdup(argv[0]); + } else { + program = resolve_path(argv[0]); + } + if (!program) { + sway_assert(program, "Unable to resolve IPC permit target '%s'." + " will issue empty policy", argv[0]); + assign_perms = false; + program = strdup(argv[0]); + } + + struct feature_policy *policy = get_feature_policy(program); + if (assign_perms) { + policy->features |= get_features(argc, argv, &error); + } sway_log(L_DEBUG, "Permissions granted to %s for features %d", policy->program, policy->features); + free(program); return cmd_results_new(CMD_SUCCESS, NULL, NULL); } @@ -65,11 +84,25 @@ struct cmd_results *cmd_reject(int argc, char **argv) { return error; } - struct feature_policy *policy = get_feature_policy(argv[0]); + char *program = NULL; + if (!strcmp(argv[0], "*")) { + program = strdup(argv[0]); + } else { + program = resolve_path(argv[0]); + } + if (!program) { + // Punt + sway_log(L_INFO, "Unable to resolve IPC reject target '%s'." + " Will use provided path", argv[0]); + program = strdup(argv[0]); + } + + struct feature_policy *policy = get_feature_policy(program); policy->features &= ~get_features(argc, argv, &error); sway_log(L_DEBUG, "Permissions granted to %s for features %d", policy->program, policy->features); + free(program); return cmd_results_new(CMD_SUCCESS, NULL, NULL); } -- cgit v1.2.3