fix: ensure mime box is large enough to read

Eyevinn · Jan 20, 2025 · fa56081 · fa56081
1 parent 38ff9db
commit fa56081
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Showing 2 changed files with 6 additions and 0 deletions.
diff --git a/mp4/mime.go b/mp4/mime.go
@@ -1,6 +1,7 @@
 package mp4
 
 import (
+	"fmt"
 	"io"
 
 	"github.com/Eyevinn/mp4ff/bits"
@@ -31,6 +32,9 @@ func DecodeMimeSR(hdr BoxHeader, startPos uint64, sr bits.SliceReader) (Box, err
 		Version: byte(versionAndFlags >> 24),
 		Flags:   versionAndFlags & flagsMask,
 	}
+	if hdr.payloadLen() < 5 {
+		return nil, fmt.Errorf("mime: box payload size %d less than 5", hdr.payloadLen())
+	}
 	rest := sr.ReadBytes(hdr.payloadLen() - 4)
 	if rest[len(rest)-1] == 0 { // zero-termination
 		b.ContentType = string(rest[:len(rest)-1])

diff --git a/mp4/testdata/fuzz/FuzzDecodeBox/77cf6e30648805ea b/mp4/testdata/fuzz/FuzzDecodeBox/77cf6e30648805ea
@@ -0,0 +1,2 @@
+go test fuzz v1
+[]byte("\x00\x00\x00\fmime0000")
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		go test fuzz v1
		[]byte("\x00\x00\x00\fmime0000")