From e17d959b6cdc3d742229d1b9fb76fbd799a464d4 Mon Sep 17 00:00:00 2001
From: ne1llee <12810839+ne1llee@users.noreply.github.com>
Date: Fri, 9 Jul 2021 14:53:04 +0800
Subject: [PATCH] Add support for PE-DLL file formats

---
 internal/magic/binary.go |  15 +++++++++++++++
 mimetype_test.go         |   1 +
 testdata/dll.dll         | Bin 0 -> 2048 bytes
 tree.go                  |   3 ++-
 4 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100755 testdata/dll.dll

diff --git a/internal/magic/binary.go b/internal/magic/binary.go
index 6bb4a939..de95dd1d 100644
--- a/internal/magic/binary.go
+++ b/internal/magic/binary.go
@@ -142,3 +142,18 @@ func Marc(raw []byte, limit uint32) bool {
 	// Field terminator is present.
 	return bytes.Contains(raw, []byte{0x1E})
 }
+
+// Microsoft PE dll
+func Dll(raw []byte, limit uint32) bool {
+	l := len(raw)
+	if l < 0x40 {
+		return false
+	}
+	signoff := binary.LittleEndian.Uint32(raw[0x3c:])
+	if uint32(l) < signoff+0x18 {
+		return false
+	}
+	characteristics := binary.LittleEndian.Uint16(raw[signoff+0x16:])
+
+	return characteristics&0x2000 == 0x2000
+}
diff --git a/mimetype_test.go b/mimetype_test.go
index 215f02bb..419c84f1 100644
--- a/mimetype_test.go
+++ b/mimetype_test.go
@@ -198,6 +198,7 @@ var files = map[string]string{
 	"xz.xz":              "application/x-xz",
 	"zip.zip":            "application/zip",
 	"zst.zst":            "application/zstd",
+	"dll.dll":            "application/vnd.microsoft.portable-executable-dll",
 }
 
 func TestDetect(t *testing.T) {
diff --git a/testdata/dll.dll b/testdata/dll.dll
new file mode 100755
index 0000000000000000000000000000000000000000..35aaadfc9b0878e00bf7ccb518920e57a3389987
GIT binary patch
literal 2048
zcmdT_O=uHQ5dPNILRy=uR1bo>l`48@=zsK}#+nK(X;Ye7MGumuX%f5HEt|yBTW^-0
zdJ>_R9`zzYJQP9j;xQoNr3aztLGYp%DTuUw^ETV8sVSZWC(L_q=FNOFZ|3dG$ek6`
z0jMYM>;UVWg+glFe-K;$>6d=I@Ri!uwMeOLBAv<UbGDVT<5@isH%%+APbGD`VCorD
z4@YBq)|yTRnwuNj%g|ck`^I4F>axobqh&cvIbt-bc|4Oy%U*RRV}n3M)3Ca6ci7$A
z#DTUZ&F6>>u9oxRGRvuCeE?{Hw#(E2I+^<CF|Zz?gQ_B8D-LSjokUq7?%k&KzoLMh
zvl9%aVoF|ePUh{U(BHMs>!Q{gYqAC`>STew$eELe!~z(rp-=xo@8iW<^dLA(4WeJ6
zu+$2?_3RfJ_`O`nGSy)OH!<Xj-0S6f5;5H4IEZnsh7iRl<sptYxE6X<|8*P8R&_a4
zJn7C?)vk26zPfDaW?YSUdDzInM2ct`7)TP?#0)I@`jt&5deMnX<X#ML<XyyZ`d+6^
z7ITQxeu3G<DJ50J5h5jsYavITVGLba+qAZ*k5iN3%B1xp1c~Lw4ih1#d^5DISb>$P
z#(YN90cLE`ewOP9eIJkwrH?CZfhamFC+Cw>CMm@@+O!lrk;geoo&{<}lT&9faL$w0
zr1Ht_W)1WsfG%>7t4{tz>PHXnQ6DkSV_wAzvQswCk>$Qq!yxT?(7~~rmVLOuX#Hqn
zEU9~5#W7hS!&A{IN>jv<+ya=UWT+e$DQW85Ddiy@nPV@cqba0`20Udpduvy#9|2ll
zQ~0_EB}c6j-KkuXIRuD(MdckWTS|Q;Z?~5sIX9wK{`YZ~`H#`xB4UBn&wEZ?tLL{=
zWvA&g&w9u$i1O5unRBnC*V5$$?n*tgs#XJN*%Pa}tNZm-K*D5=Ut*lG+*4M*7NDKq
z88D$TF&W(`XXM;;@Es_M0ZQAYZRZ`(M8pv_I!{~IhaVr0o+z5bv!8sQSC9QXb!K$y
zTk6f1cf*%ApFG^^Dx2<^mZ<TQACo1>8d>Bb`4HKq*Ic;r@2^ee&9BzWv)e@GbEPQB
OPIvI7;@`)AMZW;%!|)UU

literal 0
HcmV?d00001

diff --git a/tree.go b/tree.go
index 757ffed9..6d305e9d 100644
--- a/tree.go
+++ b/tree.go
@@ -171,7 +171,8 @@ var (
 	shp     = newMIME("application/octet-stream", ".shp", magic.Shp)
 	shx     = newMIME("application/octet-stream", ".shx", magic.Shx, shp)
 	dbf     = newMIME("application/x-dbf", ".dbf", magic.Dbf)
-	exe     = newMIME("application/vnd.microsoft.portable-executable", ".exe", magic.Exe)
+	dll     = newMIME("application/vnd.microsoft.portable-executable-dll", ".dll", magic.Dll)
+	exe     = newMIME("application/vnd.microsoft.portable-executable", ".exe", magic.Exe, dll)
 	elf     = newMIME("application/x-elf", "", magic.Elf, elfObj, elfExe, elfLib, elfDump)
 	elfObj  = newMIME("application/x-object", "", magic.ElfObj)
 	elfExe  = newMIME("application/x-executable", "", magic.ElfExe)