diff options
| -rw-r--r-- | pkg/abi/linux/sem.go | 11 | ||||
| -rw-r--r-- | pkg/sentry/fs/proc/sys.go | 1 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/proc/tasks_sys.go | 1 | ||||
| -rw-r--r-- | pkg/sentry/kernel/semaphore/semaphore.go | 20 | ||||
| -rw-r--r-- | test/syscalls/linux/proc.cc | 23 |
5 files changed, 46 insertions, 10 deletions
diff --git a/pkg/abi/linux/sem.go b/pkg/abi/linux/sem.go index 1b2f76c0b..167d2ff74 100644 --- a/pkg/abi/linux/sem.go +++ b/pkg/abi/linux/sem.go @@ -32,6 +32,17 @@ const ( SEM_STAT_ANY = 20 ) +// Information about system-wide sempahore limits and parameters. +// +// Source: include/uapi/linux/sem.h +const ( + SEMMNI = 32000 + SEMMSL = 32000 + SEMMNS = SEMMNI * SEMMSL + SEMOPM = 500 + SEMVMX = 32767 +) + const SEM_UNDO = 0x1000 // Sembuf is equivalent to struct sembuf. diff --git a/pkg/sentry/fs/proc/sys.go b/pkg/sentry/fs/proc/sys.go index f8aad2dbd..b998fb75d 100644 --- a/pkg/sentry/fs/proc/sys.go +++ b/pkg/sentry/fs/proc/sys.go @@ -84,6 +84,7 @@ func (p *proc) newKernelDir(ctx context.Context, msrc *fs.MountSource) *fs.Inode children := map[string]*fs.Inode{ "hostname": newProcInode(ctx, &h, msrc, fs.SpecialFile, nil), + "sem": newStaticProcInode(ctx, msrc, []byte(fmt.Sprintf("%d\t%d\t%d\t%d\n", linux.SEMMSL, linux.SEMMNS, linux.SEMOPM, linux.SEMMNI))), "shmall": newStaticProcInode(ctx, msrc, []byte(strconv.FormatUint(linux.SHMALL, 10))), "shmmax": newStaticProcInode(ctx, msrc, []byte(strconv.FormatUint(linux.SHMMAX, 10))), "shmmni": newStaticProcInode(ctx, msrc, []byte(strconv.FormatUint(linux.SHMMNI, 10))), diff --git a/pkg/sentry/fsimpl/proc/tasks_sys.go b/pkg/sentry/fsimpl/proc/tasks_sys.go index 7c7afdcfa..25c407d98 100644 --- a/pkg/sentry/fsimpl/proc/tasks_sys.go +++ b/pkg/sentry/fsimpl/proc/tasks_sys.go @@ -44,6 +44,7 @@ func (fs *filesystem) newSysDir(ctx context.Context, root *auth.Credentials, k * return fs.newStaticDir(ctx, root, map[string]kernfs.Inode{ "kernel": fs.newStaticDir(ctx, root, map[string]kernfs.Inode{ "hostname": fs.newInode(ctx, root, 0444, &hostnameData{}), + "sem": fs.newInode(ctx, root, 0444, newStaticFile(fmt.Sprintf("%d\t%d\t%d\t%d\n", linux.SEMMSL, linux.SEMMNS, linux.SEMOPM, linux.SEMMNI))), "shmall": fs.newInode(ctx, root, 0444, shmData(linux.SHMALL)), "shmmax": fs.newInode(ctx, root, 0444, shmData(linux.SHMMAX)), "shmmni": fs.newInode(ctx, root, 0444, shmData(linux.SHMMNI)), diff --git a/pkg/sentry/kernel/semaphore/semaphore.go b/pkg/sentry/kernel/semaphore/semaphore.go index b99c0bffa..335be8edd 100644 --- a/pkg/sentry/kernel/semaphore/semaphore.go +++ b/pkg/sentry/kernel/semaphore/semaphore.go @@ -29,17 +29,17 @@ import ( ) const ( - valueMax = 32767 // SEMVMX + // Maximum semaphore value. + valueMax = linux.SEMVMX - // semaphoresMax is "maximum number of semaphores per semaphore ID" (SEMMSL). - semaphoresMax = 32000 + // Maximum number of semaphore sets. + setsMax = linux.SEMMNI - // setMax is "system-wide limit on the number of semaphore sets" (SEMMNI). - setsMax = 32000 + // Maximum number of semaphroes in a semaphore set. + semsMax = linux.SEMMSL - // semaphoresTotalMax is "system-wide limit on the number of semaphores" - // (SEMMNS = SEMMNI*SEMMSL). - semaphoresTotalMax = 1024000000 + // Maximum number of semaphores in all semaphroe sets. + semsTotalMax = linux.SEMMNS ) // Registry maintains a set of semaphores that can be found by key or ID. @@ -122,7 +122,7 @@ func NewRegistry(userNS *auth.UserNamespace) *Registry { // be found. If exclusive is true, it fails if a set with the same key already // exists. func (r *Registry) FindOrCreate(ctx context.Context, key, nsems int32, mode linux.FileMode, private, create, exclusive bool) (*Set, error) { - if nsems < 0 || nsems > semaphoresMax { + if nsems < 0 || nsems > semsMax { return nil, syserror.EINVAL } @@ -166,7 +166,7 @@ func (r *Registry) FindOrCreate(ctx context.Context, key, nsems int32, mode linu if len(r.semaphores) >= setsMax { return nil, syserror.EINVAL } - if r.totalSems() > int(semaphoresTotalMax-nsems) { + if r.totalSems() > int(semsTotalMax-nsems) { return nil, syserror.EINVAL } diff --git a/test/syscalls/linux/proc.cc b/test/syscalls/linux/proc.cc index f43a41891..575be014c 100644 --- a/test/syscalls/linux/proc.cc +++ b/test/syscalls/linux/proc.cc @@ -17,6 +17,7 @@ #include <fcntl.h> #include <limits.h> #include <linux/magic.h> +#include <linux/sem.h> #include <sched.h> #include <signal.h> #include <stddef.h> @@ -2409,6 +2410,28 @@ TEST(ProcFilesystems, PresenceOfShmMaxMniAll) { ASSERT_LE(shmall, ULONG_MAX - (1UL << 24)); } +TEST(ProcFilesystems, PresenceOfSem) { + uint32_t semmsl = 0; + uint32_t semmns = 0; + uint32_t semopm = 0; + uint32_t semmni = 0; + std::string proc_file; + proc_file = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/sys/kernel/sem")); + ASSERT_FALSE(proc_file.empty()); + std::vector<absl::string_view> sem_limits = + absl::StrSplit(proc_file, absl::ByAnyChar("\t"), absl::SkipWhitespace()); + ASSERT_EQ(sem_limits.size(), 4); + ASSERT_TRUE(absl::SimpleAtoi(sem_limits[0], &semmsl)); + ASSERT_TRUE(absl::SimpleAtoi(sem_limits[1], &semmns)); + ASSERT_TRUE(absl::SimpleAtoi(sem_limits[2], &semopm)); + ASSERT_TRUE(absl::SimpleAtoi(sem_limits[3], &semmni)); + + ASSERT_EQ(semmsl, SEMMSL); + ASSERT_EQ(semmns, SEMMNS); + ASSERT_EQ(semopm, SEMOPM); + ASSERT_EQ(semmni, SEMMNI); +} + // Check that /proc/mounts is a symlink to self/mounts. TEST(ProcMounts, IsSymlink) { auto link = ASSERT_NO_ERRNO_AND_VALUE(ReadLink("/proc/mounts")); |