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| author | Eelco Dolstra <edolstra@gmail.com> | 2017-05-30T11·55+0200 |
|---|---|---|
| committer | Eelco Dolstra <edolstra@gmail.com> | 2017-05-30T11·59+0200 |
| commit | 2ac99a32dab0d2ea59cb9e926f6d6d5b7ef638c6 (patch) | |
| tree | 44acf2a20f958ab8d1fe465aa392b2984ae95b3e | |
| parent | d798349ede3d6eb6e92a2e4f95f6b2179407ceb9 (diff) | |
Add a seccomp rule to disallow setxattr()
| -rw-r--r-- | src/libstore/build.cc | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/src/libstore/build.cc b/src/libstore/build.cc index 09cc2709ab79..0a10efaed1d6 100644 --- a/src/libstore/build.cc +++ b/src/libstore/build.cc @@ -2315,8 +2315,8 @@ void setupSeccomp() seccomp_arch_add(ctx, SCMP_ARCH_X86) != 0) throw SysError("unable to add 32-bit seccomp architecture"); + /* Prevent builders from creating setuid/setgid binaries. */ for (int perm : { S_ISUID, S_ISGID }) { - // TODO: test chmod and fchmod. if (seccomp_rule_add(ctx, SCMP_ACT_ERRNO(EPERM), SCMP_SYS(chmod), 1, SCMP_A1(SCMP_CMP_MASKED_EQ, perm, perm)) != 0) throw SysError("unable to add seccomp rule"); @@ -2330,6 +2330,14 @@ void setupSeccomp() throw SysError("unable to add seccomp rule"); } + /* Prevent builders from creating EAs or ACLs. Not all filesystems + support these, and they're not allowed in the Nix store because + they're not representable in the NAR serialisation. */ + if (seccomp_rule_add(ctx, SCMP_ACT_ERRNO(ENOTSUP), SCMP_SYS(setxattr), 0) != 0 || + seccomp_rule_add(ctx, SCMP_ACT_ERRNO(ENOTSUP), SCMP_SYS(lsetxattr), 0) != 0 || + seccomp_rule_add(ctx, SCMP_ACT_ERRNO(ENOTSUP), SCMP_SYS(fsetxattr), 0) != 0) + throw SysError("unable to add seccomp rule"); + if (seccomp_load(ctx) != 0) throw SysError("unable to load seccomp BPF program"); #endif |