From a1c933dabd0e1c54a412f3f84ae0aa58115c6067 Mon Sep 17 00:00:00 2001
From: Even Rouault <even.rouault@spatialys.com>
Date: Thu, 24 Feb 2022 22:26:02 +0100
Subject: [PATCH] tif_jbig.c: fix crash when reading a file with multiple IFD
 in memory-mapped mode and when bit reversal is needed (fixes #385)

---
 libtiff/tif_jbig.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/libtiff/tif_jbig.c b/libtiff/tif_jbig.c
index 74086338..8bfa4cef 100644
--- a/libtiff/tif_jbig.c
+++ b/libtiff/tif_jbig.c
@@ -209,6 +209,16 @@ int TIFFInitJBIG(TIFF* tif, int scheme)
 	 */
 	tif->tif_flags |= TIFF_NOBITREV;
 	tif->tif_flags &= ~TIFF_MAPPED;
+	/* We may have read from a previous IFD and thus set TIFF_BUFFERMMAP and
+	 * cleared TIFF_MYBUFFER. It is necessary to restore them to their initial
+	 * value to be consistent with the state of a non-memory mapped file.
+	 */
+	if (tif->tif_flags&TIFF_BUFFERMMAP) {
+		tif->tif_rawdata = NULL;
+		tif->tif_rawdatasize = 0;
+		tif->tif_flags &= ~TIFF_BUFFERMMAP;
+		tif->tif_flags |= TIFF_MYBUFFER;
+	}
 
 	/* Setup the function pointers for encode, decode, and cleanup. */
 	tif->tif_setupdecode = JBIGSetupDecode;
-- 
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