zlib: Fixed copying causing cache corruption when zlib_save wasn't set.

dovecot.index.cache entries were broken/missing if:
- The zlib plugin is enabled;
- The zlib_save/zlib_save_level options are NOT enabled;
- The source message being copied is compressed;
- The mail_log plugin is logging "copy" events;
- The mail_log_fields setting includes at least one message header;
- The destination mailbox folder has an index file that is recording the
logged headers;
- The source mailbox folder does NOT have an index file recording the
logged headers.

Found by Robert L Mathews.

diff --git a/src/plugins/zlib/zlib-plugin.c b/src/plugins/zlib/zlib-plugin.c
index 9884fa82a7c92135c006e5e57c805d4c2a28f584..92995e3c531809ec34eccde4128eafa88675ba4a 100644 (file)
--- a/src/plugins/zlib/zlib-plugin.c
+++ b/src/plugins/zlib/zlib-plugin.c
@@ -26,6 +26,11 @@
 #define MAX_INBUF_SIZE (1024*1024)
 #define ZLIB_MAIL_CACHE_EXPIRE_MSECS (60*1000)
 
+struct zlib_mail {
+       union mail_module_context module_ctx;
+       bool verifying_save;
+};
+
 struct zlib_transaction_context {
        union mailbox_transaction_module_context module_ctx;
 
@@ -112,16 +117,15 @@ static int zlib_istream_opened(struct mail *_mail, struct istream **stream)
        struct zlib_user *zuser = ZLIB_USER_CONTEXT(_mail->box->storage->user);
        struct zlib_mail_cache *cache = &zuser->cache;
        struct mail_private *mail = (struct mail_private *)_mail;
-       union mail_module_context *zmail = ZLIB_MAIL_CONTEXT(mail);
+       struct zlib_mail *zmail = ZLIB_MAIL_CONTEXT(mail);
        struct istream *input;
        const struct compression_handler *handler;
 
-       /* don't uncompress input when we are reading a mail that we're just
-          in the middle of saving, and we didn't do the compression ourself.
-          in such situation we're probably checking if the user-given input
-          looks compressed */
-       if (_mail->saving && zuser->save_handler == NULL)
-               return zmail->super.istream_opened(_mail, stream);
+       if (zmail->verifying_save) {
+               /* zlib_mail_save_finish() is verifying that the user-given
+                  input doesn't look compressed. */
+               return zmail->module_ctx.super.istream_opened(_mail, stream);
+       }
 
        if (cache->uid == _mail->uid && cache->box == _mail->box) {
                /* use the cached stream. when doing partial reads it should
@@ -129,7 +133,7 @@ static int zlib_istream_opened(struct mail *_mail, struct istream **stream)
                i_stream_unref(stream);
                i_stream_seek(cache->input, 0);
                *stream = i_stream_create_limit(cache->input, (uoff_t)-1);
-               return zmail->super.istream_opened(_mail, stream);
+               return zmail->module_ctx.super.istream_opened(_mail, stream);
        }
 
        handler = compression_detect_handler(*stream);
@@ -147,7 +151,7 @@ static int zlib_istream_opened(struct mail *_mail, struct istream **stream)
 
                *stream = zlib_mail_cache_open(zuser, _mail, *stream);
        }
-       return zmail->super.istream_opened(_mail, stream);
+       return zmail->module_ctx.super.istream_opened(_mail, stream);
 }
 
 static void zlib_mail_allocated(struct mail *_mail)
@@ -155,17 +159,17 @@ static void zlib_mail_allocated(struct mail *_mail)
        struct zlib_transaction_context *zt = ZLIB_CONTEXT(_mail->transaction);
        struct mail_private *mail = (struct mail_private *)_mail;
        struct mail_vfuncs *v = mail->vlast;
-       union mail_module_context *zmail;
+       struct zlib_mail *zmail;
 
        if (zt == NULL)
                return;
 
-       zmail = p_new(mail->pool, union mail_module_context, 1);
-       zmail->super = *v;
-       mail->vlast = &zmail->super;
+       zmail = p_new(mail->pool, struct zlib_mail, 1);
+       zmail->module_ctx.super = *v;
+       mail->vlast = &zmail->module_ctx.super;
 
        v->istream_opened = zlib_istream_opened;
-       MODULE_CONTEXT_SET_SELF(mail, zlib_mail_module, zmail);
+       MODULE_CONTEXT_SET(mail, zlib_mail_module, zmail);
 }
 
 static struct mailbox_transaction_context *
@@ -235,12 +239,18 @@ static int zlib_mail_save_finish(struct mail_save_context *ctx)
 {
        struct mailbox *box = ctx->transaction->box;
        union mailbox_module_context *zbox = ZLIB_CONTEXT(box);
+       struct mail_private *mail = (struct mail_private *)ctx->dest_mail;
+       struct zlib_mail *zmail = ZLIB_MAIL_CONTEXT(mail);
        struct istream *input;
+       int ret;
 
        if (zbox->super.save_finish(ctx) < 0)
                return -1;
 
-       if (mail_get_stream(ctx->dest_mail, NULL, NULL, &input) < 0)
+       zmail->verifying_save = TRUE;
+       ret = mail_get_stream(ctx->dest_mail, NULL, NULL, &input);
+       zmail->verifying_save = FALSE;
+       if (ret < 0)
                return -1;
 
        if (compression_detect_handler(input) != NULL) {