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Merge pull request #12202 from keszybz/seccomp-arm64
Fixes for S[GU]ID filter on arm64
This commit is contained in:
Lennart Poettering
GitHub
commit
3b4ce4b08c
@ -1803,9 +1803,139 @@ int seccomp_protect_hostname(void) {
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return 0;
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}
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static int seccomp_restrict_sxid(scmp_filter_ctx seccomp, mode_t m) {
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/* Checks the mode_t parameter of the following system calls:
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*
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* → chmod() + fchmod() + fchmodat()
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* → open() + creat() + openat()
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* → mkdir() + mkdirat()
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* → mknod() + mknodat()
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*
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* Returns error if *everything* failed, and 0 otherwise.
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*/
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int r = 0;
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bool any = false;
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(chmod),
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1,
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SCMP_A1(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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log_debug_errno(r, "Failed to add filter for chmod: %m");
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else
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any = true;
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(fchmod),
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1,
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SCMP_A1(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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log_debug_errno(r, "Failed to add filter for fchmod: %m");
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else
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any = true;
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(fchmodat),
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1,
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SCMP_A2(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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log_debug_errno(r, "Failed to add filter for fchmodat: %m");
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else
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any = true;
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(mkdir),
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1,
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SCMP_A1(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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log_debug_errno(r, "Failed to add filter for mkdir: %m");
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else
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any = true;
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(mkdirat),
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1,
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SCMP_A2(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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log_debug_errno(r, "Failed to add filter for mkdirat: %m");
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else
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any = true;
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(mknod),
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1,
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SCMP_A1(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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log_debug_errno(r, "Failed to add filter for mknod: %m");
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else
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any = true;
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(mknodat),
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1,
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SCMP_A2(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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log_debug_errno(r, "Failed to add filter for mknodat: %m");
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else
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any = true;
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#if SCMP_SYS(open) > 0
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(open),
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2,
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SCMP_A1(SCMP_CMP_MASKED_EQ, O_CREAT, O_CREAT),
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SCMP_A2(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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log_debug_errno(r, "Failed to add filter for open: %m");
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else
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any = true;
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#endif
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(openat),
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2,
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SCMP_A2(SCMP_CMP_MASKED_EQ, O_CREAT, O_CREAT),
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SCMP_A3(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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log_debug_errno(r, "Failed to add filter for openat: %m");
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else
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any = true;
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(creat),
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1,
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SCMP_A1(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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log_debug_errno(r, "Failed to add filter for creat: %m");
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else
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any = true;
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return any ? 0 : r;
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}
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int seccomp_restrict_suid_sgid(void) {
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uint32_t arch;
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int r;
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int r, k;
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SECCOMP_FOREACH_LOCAL_ARCH(arch) {
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_cleanup_(seccomp_releasep) scmp_filter_ctx seccomp = NULL;
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@ -1814,114 +1944,16 @@ int seccomp_restrict_suid_sgid(void) {
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if (r < 0)
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return r;
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/* Checks the mode_t parameter of the following system calls:
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*
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* → chmod() + fchmod() + fchmodat()
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* → open() + creat() + openat()
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* → mkdir() + mkdirat()
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* → mknod() + mknodat()
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*/
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r = seccomp_restrict_sxid(seccomp, S_ISUID);
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if (r < 0)
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log_debug_errno(r, "Failed to add suid rule for architecture %s, ignoring: %m", seccomp_arch_to_string(arch));
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for (unsigned bit = 0; bit < 2; bit ++) {
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/* Block S_ISUID in the first iteration, S_ISGID in the second */
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mode_t m = bit == 0 ? S_ISUID : S_ISGID;
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k = seccomp_restrict_sxid(seccomp, S_ISGID);
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if (k < 0)
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log_debug_errno(r, "Failed to add sgid rule for architecture %s, ignoring: %m", seccomp_arch_to_string(arch));
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(chmod),
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1,
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SCMP_A1(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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break;
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(fchmod),
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1,
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SCMP_A1(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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break;
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(fchmodat),
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1,
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SCMP_A2(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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break;
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(mkdir),
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1,
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SCMP_A1(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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break;
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(mkdirat),
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1,
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SCMP_A2(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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break;
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(mknod),
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1,
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SCMP_A1(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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break;
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(mknodat),
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1,
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SCMP_A2(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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break;
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(open),
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2,
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SCMP_A1(SCMP_CMP_MASKED_EQ, O_CREAT, O_CREAT),
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SCMP_A2(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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break;
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(openat),
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2,
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SCMP_A2(SCMP_CMP_MASKED_EQ, O_CREAT, O_CREAT),
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SCMP_A3(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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break;
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r = seccomp_rule_add_exact(
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seccomp,
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SCMP_ACT_ERRNO(EPERM),
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SCMP_SYS(creat),
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1,
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SCMP_A1(SCMP_CMP_MASKED_EQ, m, m));
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if (r < 0)
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break;
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}
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if (r < 0) {
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log_debug_errno(r, "Failed to add suid/sgid rule for architecture %s, skipping: %m", seccomp_arch_to_string(arch));
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if (r < 0 && k < 0)
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continue;
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}
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r = seccomp_load(seccomp);
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if (IN_SET(r, -EPERM, -EACCES))
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@ -7,6 +7,7 @@
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#include <sys/mman.h>
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#include <sys/personality.h>
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#include <sys/shm.h>
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#include <sys/syscall.h>
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#include <sys/types.h>
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#include <unistd.h>
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@ -763,9 +764,14 @@ static void test_lock_personality(void) {
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static int real_open(const char *path, int flags, mode_t mode) {
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/* glibc internally calls openat() when open() is requested. Let's hence define our own wrapper for
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* testing purposes that calls the real syscall. */
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* testing purposes that calls the real syscall, on architectures where SYS_open is defined. On
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* other architectures, let's just fall back to the glibc call. */
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#ifdef SYS_open
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return (int) syscall(SYS_open, path, flags, mode);
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#else
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return open(path, flags, mode);
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#endif
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}
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static void test_restrict_suid_sgid(void) {
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