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fix(seccomp): remove the narrower read rule to keep the broader intent #4744

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fix(seccomp): remove the narrower read rule to keep the broader intent #4744

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3 changes: 0 additions & 3 deletions src/discof/rpc/fd_rpcserv_tile.seccomppolicy
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Original file line number Diff line number Diff line change
Expand Up @@ -68,8 +68,5 @@ close: (not (or (eq (arg 0) 2)
# arg 2 is the timeout.
poll: (eq (arg 2) 0)

# blockstore: read archival file
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Don't you need to add blockstore_fd to the above read rule as well then?

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@eternalsakura13 eternalsakura13 Apr 12, 2025 •
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If blockstore_fd is not one of the three disallowed file descriptors, then it’s already implicitly allowed by the first rule. In that case, you can simply keep the first rule.

see #4740

read: (eq (arg 0) blockstore_fd)

# blockstore: lseek archival file
lseek: (eq (arg 0) blockstore_fd)
68 changes: 37 additions & 31 deletions src/discof/rpc/generated/fd_rpcserv_tile_seccomp.h
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Original file line number Diff line number Diff line change
Expand Up @@ -21,89 +21,95 @@
#else
# error "Target architecture is unsupported by seccomp."
#endif
static const unsigned int sock_filter_policy_fd_rpcserv_tile_instr_cnt = 47;
static const unsigned int sock_filter_policy_fd_rpcserv_tile_instr_cnt = 50;

static void populate_sock_filter_policy_fd_rpcserv_tile( ulong out_cnt, struct sock_filter * out, unsigned int logfile_fd, unsigned int rpcserv_socket_fd, unsigned int blockstore_fd) {
FD_TEST( out_cnt >= 47 );
struct sock_filter filter[47] = {
FD_TEST( out_cnt >= 50 );
struct sock_filter filter[50] = {
/* Check: Jump to RET_KILL_PROCESS if the script's arch != the runtime arch */
BPF_STMT( BPF_LD | BPF_W | BPF_ABS, ( offsetof( struct seccomp_data, arch ) ) ),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, ARCH_NR, 0, /* RET_KILL_PROCESS */ 43 ),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, ARCH_NR, 0, /* RET_KILL_PROCESS */ 46 ),
/* loading syscall number in accumulator */
BPF_STMT( BPF_LD | BPF_W | BPF_ABS, ( offsetof( struct seccomp_data, nr ) ) ),
/* allow write based on expression */
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SYS_write, /* check_write */ 9, 0 ),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SYS_write, /* check_write */ 8, 0 ),
/* allow fsync based on expression */
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SYS_fsync, /* check_fsync */ 12, 0 ),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SYS_fsync, /* check_fsync */ 11, 0 ),
/* allow accept4 based on expression */
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SYS_accept4, /* check_accept4 */ 13, 0 ),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SYS_accept4, /* check_accept4 */ 12, 0 ),
/* allow read based on expression */
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SYS_read, /* check_read */ 20, 0 ),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SYS_read, /* check_read */ 19, 0 ),
/* allow sendto based on expression */
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SYS_sendto, /* check_sendto */ 21, 0 ),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SYS_sendto, /* check_sendto */ 24, 0 ),
/* allow close based on expression */
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SYS_close, /* check_close */ 26, 0 ),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SYS_close, /* check_close */ 29, 0 ),
/* allow poll based on expression */
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SYS_poll, /* check_poll */ 31, 0 ),
/* allow read based on expression */
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SYS_read, /* check_read */ 16, 0 ),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SYS_poll, /* check_poll */ 34, 0 ),
/* allow lseek based on expression */
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SYS_lseek, /* check_lseek */ 31, 0 ),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SYS_lseek, /* check_lseek */ 35, 0 ),
/* none of the syscalls matched */
{ BPF_JMP | BPF_JA, 0, 0, /* RET_KILL_PROCESS */ 32 },
{ BPF_JMP | BPF_JA, 0, 0, /* RET_KILL_PROCESS */ 36 },
// check_write:
/* load syscall argument 0 in accumulator */
BPF_STMT( BPF_LD | BPF_W | BPF_ABS, offsetof(struct seccomp_data, args[0])),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, 2, /* RET_ALLOW */ 31, /* lbl_1 */ 0 ),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, 2, /* RET_ALLOW */ 35, /* lbl_1 */ 0 ),
// lbl_1:
/* load syscall argument 0 in accumulator */
BPF_STMT( BPF_LD | BPF_W | BPF_ABS, offsetof(struct seccomp_data, args[0])),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, logfile_fd, /* RET_ALLOW */ 29, /* RET_KILL_PROCESS */ 28 ),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, logfile_fd, /* RET_ALLOW */ 33, /* RET_KILL_PROCESS */ 32 ),
// check_fsync:
/* load syscall argument 0 in accumulator */
BPF_STMT( BPF_LD | BPF_W | BPF_ABS, offsetof(struct seccomp_data, args[0])),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, logfile_fd, /* RET_ALLOW */ 27, /* RET_KILL_PROCESS */ 26 ),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, logfile_fd, /* RET_ALLOW */ 31, /* RET_KILL_PROCESS */ 30 ),
// check_accept4:
/* load syscall argument 0 in accumulator */
BPF_STMT( BPF_LD | BPF_W | BPF_ABS, offsetof(struct seccomp_data, args[0])),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, rpcserv_socket_fd, /* lbl_2 */ 0, /* RET_KILL_PROCESS */ 24 ),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, rpcserv_socket_fd, /* lbl_2 */ 0, /* RET_KILL_PROCESS */ 28 ),
// lbl_2:
/* load syscall argument 1 in accumulator */
BPF_STMT( BPF_LD | BPF_W | BPF_ABS, offsetof(struct seccomp_data, args[1])),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, 0, /* lbl_3 */ 0, /* RET_KILL_PROCESS */ 22 ),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, 0, /* lbl_3 */ 0, /* RET_KILL_PROCESS */ 26 ),
// lbl_3:
/* load syscall argument 2 in accumulator */
BPF_STMT( BPF_LD | BPF_W | BPF_ABS, offsetof(struct seccomp_data, args[2])),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, 0, /* lbl_4 */ 0, /* RET_KILL_PROCESS */ 20 ),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, 0, /* lbl_4 */ 0, /* RET_KILL_PROCESS */ 24 ),
// lbl_4:
/* load syscall argument 3 in accumulator */
BPF_STMT( BPF_LD | BPF_W | BPF_ABS, offsetof(struct seccomp_data, args[3])),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SOCK_CLOEXEC|SOCK_NONBLOCK, /* RET_ALLOW */ 19, /* RET_KILL_PROCESS */ 18 ),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, SOCK_CLOEXEC|SOCK_NONBLOCK, /* RET_ALLOW */ 23, /* RET_KILL_PROCESS */ 22 ),
// check_read:
/* load syscall argument 0 in accumulator */
BPF_STMT( BPF_LD | BPF_W | BPF_ABS, offsetof(struct seccomp_data, args[0])),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, blockstore_fd, /* RET_ALLOW */ 17, /* RET_KILL_PROCESS */ 16 ),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, 2, /* RET_KILL_PROCESS */ 20, /* lbl_5 */ 0 ),
// lbl_5:
/* load syscall argument 0 in accumulator */
BPF_STMT( BPF_LD | BPF_W | BPF_ABS, offsetof(struct seccomp_data, args[0])),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, logfile_fd, /* RET_KILL_PROCESS */ 18, /* lbl_6 */ 0 ),
// lbl_6:
/* load syscall argument 0 in accumulator */
BPF_STMT( BPF_LD | BPF_W | BPF_ABS, offsetof(struct seccomp_data, args[0])),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, rpcserv_socket_fd, /* RET_KILL_PROCESS */ 16, /* RET_ALLOW */ 17 ),
// check_sendto:
/* load syscall argument 0 in accumulator */
BPF_STMT( BPF_LD | BPF_W | BPF_ABS, offsetof(struct seccomp_data, args[0])),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, 2, /* RET_KILL_PROCESS */ 14, /* lbl_5 */ 0 ),
// lbl_5:
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, 2, /* RET_KILL_PROCESS */ 14, /* lbl_7 */ 0 ),
// lbl_7:
/* load syscall argument 0 in accumulator */
BPF_STMT( BPF_LD | BPF_W | BPF_ABS, offsetof(struct seccomp_data, args[0])),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, logfile_fd, /* RET_KILL_PROCESS */ 12, /* lbl_6 */ 0 ),
// lbl_6:
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, logfile_fd, /* RET_KILL_PROCESS */ 12, /* lbl_8 */ 0 ),
// lbl_8:
/* load syscall argument 0 in accumulator */
BPF_STMT( BPF_LD | BPF_W | BPF_ABS, offsetof(struct seccomp_data, args[0])),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, rpcserv_socket_fd, /* RET_KILL_PROCESS */ 10, /* RET_ALLOW */ 11 ),
// check_close:
/* load syscall argument 0 in accumulator */
BPF_STMT( BPF_LD | BPF_W | BPF_ABS, offsetof(struct seccomp_data, args[0])),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, 2, /* RET_KILL_PROCESS */ 8, /* lbl_7 */ 0 ),
// lbl_7:
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, 2, /* RET_KILL_PROCESS */ 8, /* lbl_9 */ 0 ),
// lbl_9:
/* load syscall argument 0 in accumulator */
BPF_STMT( BPF_LD | BPF_W | BPF_ABS, offsetof(struct seccomp_data, args[0])),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, logfile_fd, /* RET_KILL_PROCESS */ 6, /* lbl_8 */ 0 ),
// lbl_8:
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, logfile_fd, /* RET_KILL_PROCESS */ 6, /* lbl_10 */ 0 ),
// lbl_10:
/* load syscall argument 0 in accumulator */
BPF_STMT( BPF_LD | BPF_W | BPF_ABS, offsetof(struct seccomp_data, args[0])),
BPF_JUMP( BPF_JMP | BPF_JEQ | BPF_K, rpcserv_socket_fd, /* RET_KILL_PROCESS */ 4, /* RET_ALLOW */ 5 ),
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