Revision e1d911dd4c7b76a5a8cec0f5c8de15981e34da83 authored by Johannes Schindelin on 12 September 2019, 12:54:05 UTC, committed by Johannes Schindelin on 04 December 2019, 12:20:05 UTC
The backslash character is not a valid part of a file name on Windows. Hence it is dangerous to allow writing files that were unpacked from tree objects, when the stored file name contains a backslash character: it will be misinterpreted as directory separator. This not only causes ambiguity when a tree contains a blob `a\b` and a tree `a` that contains a blob `b`, but it also can be used as part of an attack vector to side-step the careful protections against writing into the `.git/` directory during a clone of a maliciously-crafted repository. Let's prevent that, addressing CVE-2019-1354. Note: we guard against backslash characters in tree objects' file names _only_ on Windows (because on other platforms, even on those where NTFS volumes can be mounted, the backslash character is _not_ a directory separator), and _only_ when `core.protectNTFS = true` (because users might need to generate tree objects for other platforms, of course without touching the worktree, e.g. using `git update-index --cacheinfo`). Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
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sha1dc_git.h
/*
* This code is included at the end of sha1dc/sha1.h with the
* SHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_H macro.
*/
/*
* Same as SHA1DCFinal, but convert collision attack case into a verbose die().
*/
void git_SHA1DCFinal(unsigned char [20], SHA1_CTX *);
/*
* Same as SHA1DCUpdate, but adjust types to match git's usual interface.
*/
void git_SHA1DCUpdate(SHA1_CTX *ctx, const void *data, unsigned long len);
#define platform_SHA_CTX SHA1_CTX
#define platform_SHA1_Init SHA1DCInit
#define platform_SHA1_Update git_SHA1DCUpdate
#define platform_SHA1_Final git_SHA1DCFinal
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