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wasi: fixes bug where zero length iovec breaks fd_read (#1402)

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We should tolerate noop input vs break. This fixes where a zero length
iovec would short circuit latter ones.

Signed-off-by: Adrian Cole <adrian@tetrate.io>
This commit is contained in:
Crypt Keeper
2023-04-25 14:43:43 +08:00
committed by GitHub
parent 3c1c76e2a1
commit 4c2638e41e
2 changed files with 14 additions and 8 deletions
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4
imports/wasi_snapshot_preview1/fs.go
View File

@@ -708,6 +708,10 @@ func fdReadOrPread(mod api.Module, params []uint64, isPread bool) syscall.Errno
offset := le.Uint32(iovsBuf[iovsPos:])
l := le.Uint32(iovsBuf[iovsPos+4:])
if l == 0 { // A zero length iovec could be ahead of another.
continue
}
b, ok := mem.Read(offset, l)
if !ok {
return syscall.EFAULT

18
imports/wasi_snapshot_preview1/fs_test.go
View File

@@ -1662,19 +1662,21 @@ func Test_fdRead(t *testing.T) {
iovs := uint32(1) // arbitrary offset
initialMemory := []byte{
'?', // `iovs` is after this
18, 0, 0, 0, // = iovs[0].offset
26, 0, 0, 0, // = iovs[0].offset
4, 0, 0, 0, // = iovs[0].length
23, 0, 0, 0, // = iovs[1].offset
2, 0, 0, 0, // = iovs[1].length
31, 0, 0, 0, // = iovs[1].offset
0, 0, 0, 0, // = iovs[1].length == 0 !!
31, 0, 0, 0, // = iovs[2].offset
2, 0, 0, 0, // = iovs[2].length
'?',
}
iovsCount := uint32(2) // The count of iovs
resultNread := uint32(26) // arbitrary offset
iovsCount := uint32(3) // The count of iovs
resultNread := uint32(34) // arbitrary offset
expectedMemory := append(
initialMemory,
'w', 'a', 'z', 'e', // iovs[0].length bytes
'?', // iovs[1].offset is after this
'r', 'o', // iovs[1].length bytes
'?', // iovs[2].offset is after this
'r', 'o', // iovs[2].length bytes
'?', // resultNread is after this
6, 0, 0, 0, // sum(iovs[...].length) == length of "wazero"
'?',
@@ -1687,7 +1689,7 @@ func Test_fdRead(t *testing.T) {
requireErrnoResult(t, wasip1.ErrnoSuccess, mod, wasip1.FdReadName, uint64(fd), uint64(iovs), uint64(iovsCount), uint64(resultNread))
require.Equal(t, `
==> wasi_snapshot_preview1.fd_read(fd=4,iovs=1,iovs_len=2)
==> wasi_snapshot_preview1.fd_read(fd=4,iovs=1,iovs_len=3)
<== (nread=6,errno=ESUCCESS)
`, "\n"+log.String())