Fix a crash with --format=alone if other filters than LZMA

are specified on the command line.

diff --git a/src/lzma/args.c b/src/lzma/args.c
index 24fc093..4393a6b 100644 (file)
--- a/src/lzma/args.c
+++ b/src/lzma/args.c
@@ -462,6 +462,15 @@ set_compression_settings(void)
        // Terminate the filter options array.
        opt_filters[filter_count].id = LZMA_VLI_VALUE_UNKNOWN;
 
+       // If we are using the LZMA_Alone format, allow exactly one filter
+       // which has to be LZMA.
+       if (opt_header == HEADER_ALONE && (filter_count != 1
+                       || opt_filters[0].id != LZMA_FILTER_LZMA)) {
+               errmsg(V_ERROR, _("With --format=alone only the LZMA filter "
+                               "is supported"));
+               my_exit(ERROR);
+       }
+
        // Optimize the filter chain a little by removing all
        // Copy filters.
        for (size_t i = 0; opt_filters[i].id != LZMA_VLI_VALUE_UNKNOWN; ++i) {