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authorMichael Vogt <mvo@ubuntu.com>2015-05-22 15:28:53 +0200
committerMichael Vogt <mvo@ubuntu.com>2015-05-22 17:52:41 +0200
commit7c4511322e22c3d97c6d892204af67d240416e69 (patch)
tree158e18fc2728599166c9803b3e58dea5e76c2827 /methods/server.cc
parent4694e07d450baa13fa04482752ca369a5797c640 (diff)
Fix endless loop in apt-get update that can cause disk fillup
The apt http code parses Content-Length and Content-Range. For both requests the variable "Size" is used and the semantic for this Size is the total file size. However Content-Length is not the entire file size for partital file requests. For servers that send the Content-Range header first and then the Content-Length header this can lead to globbing of Size so that its less than the real file size. This may lead to a subsequent passing of a negative number into the CircleBuf which leads to a endless loop that writes data. Thanks to Anton Blanchard for the analysis and initial patch. LP: #1445239
Diffstat (limited to 'methods/server.cc')
-rw-r--r--methods/server.cc20
1 files changed, 15 insertions, 5 deletions
diff --git a/methods/server.cc b/methods/server.cc
index e321e0230..ba0a8864b 100644
--- a/methods/server.cc
+++ b/methods/server.cc
@@ -164,15 +164,22 @@ bool ServerState::HeaderLine(string Line)
Encoding = Stream;
HaveContent = true;
- unsigned long long * SizePtr = &Size;
+ unsigned long long * DownloadSizePtr = &DownloadSize;
if (Result == 416)
- SizePtr = &JunkSize;
+ DownloadSizePtr = &JunkSize;
- *SizePtr = strtoull(Val.c_str(), NULL, 10);
- if (*SizePtr >= std::numeric_limits<unsigned long long>::max())
+ *DownloadSizePtr = strtoull(Val.c_str(), NULL, 10);
+ if (*DownloadSizePtr >= std::numeric_limits<unsigned long long>::max())
return _error->Errno("HeaderLine", _("The HTTP server sent an invalid Content-Length header"));
- else if (*SizePtr == 0)
+ else if (*DownloadSizePtr == 0)
HaveContent = false;
+
+ // On partial content (206) the Content-Length less than the real
+ // size, so do not set it here but leave that to the Content-Range
+ // header instead
+ if(Result != 206 && Size == 0)
+ Size = DownloadSize;
+
return true;
}
@@ -193,6 +200,9 @@ bool ServerState::HeaderLine(string Line)
return _error->Error(_("The HTTP server sent an invalid Content-Range header"));
if ((unsigned long long)StartPos > Size)
return _error->Error(_("This HTTP server has broken range support"));
+
+ // figure out what we will download
+ DownloadSize = Size - StartPos;
return true;
}