dispatch: protect against malicious 'hg serve --stdio' invocations (sec)
Some shared-ssh installations assume that 'hg serve --stdio' is a safe
command to run for minimally trusted users. Unfortunately, the messy
implementation of argument parsing here meant that trying to access a
repo named '--debugger' would give the user a pdb prompt, thereby
sidestepping any hoped-for sandboxing. Serving repositories over HTTP(S)
is unaffected.
We're not currently hardening any subcommands other than 'serve'. If
your service exposes other commands to users with arbitrary repository
names, it is imperative that you defend against repository names of
'--debugger' and anything starting with '--config'.
The read-only mode of hg-ssh stopped working because it provided its hook
configuration to "hg serve --stdio" via --config parameter. This is banned for
security reasons now. This patch switches it to directly call ui.setconfig().
If your custom hosting infrastructure relies on passing --config to
"hg serve --stdio", you'll need to find a different way to get that configuration
into Mercurial, either by using ui.setconfig() as hg-ssh does in this patch,
or by placing an hgrc file someplace where Mercurial will read it.
mitrandir@fb.com provided some extra fixes for the dispatch code and
for hg-ssh in places that I overlooked.
$ cat << EOF >> $HGRCPATH
> [format]
> usegeneraldelta=yes
> EOF
$ hg init debugrevlog
$ cd debugrevlog
$ echo a > a
$ hg ci -Am adda
adding a
$ hg debugrevlog -m
format : 1
flags : inline, generaldelta
revisions : 1
merges : 0 ( 0.00%)
normal : 1 (100.00%)
revisions : 1
full : 1 (100.00%)
deltas : 0 ( 0.00%)
revision size : 44
full : 44 (100.00%)
deltas : 0 ( 0.00%)
chunks : 1
0x75 (u) : 1 (100.00%)
chunks size : 44
0x75 (u) : 44 (100.00%)
avg chain length : 0
max chain length : 0
compression ratio : 0
uncompressed data size (min/max/avg) : 43 / 43 / 43
full revision size (min/max/avg) : 44 / 44 / 44
delta size (min/max/avg) : 0 / 0 / 0
Test debugindex, with and without the --debug flag
$ hg debugindex a
rev offset length ..... linkrev nodeid p1 p2 (re)
0 0 3 .... 0 b789fdd96dc2 000000000000 000000000000 (re)
$ hg --debug debugindex a
rev offset length ..... linkrev nodeid p1 p2 (re)
0 0 3 .... 0 b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3 0000000000000000000000000000000000000000 0000000000000000000000000000000000000000 (re)
$ hg debugindex -f 1 a
rev flag offset length size ..... link p1 p2 nodeid (re)
0 0000 0 3 2 .... 0 -1 -1 b789fdd96dc2 (re)
$ hg --debug debugindex -f 1 a
rev flag offset length size ..... link p1 p2 nodeid (re)
0 0000 0 3 2 .... 0 -1 -1 b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3 (re)
debugdelta chain basic output
$ hg debugdeltachain -m
rev chain# chainlen prev delta size rawsize chainsize ratio lindist extradist extraratio
0 1 1 -1 base 44 43 44 1.02326 44 0 0.00000
$ hg debugdeltachain -m -T '{rev} {chainid} {chainlen}\n'
0 1 1
$ hg debugdeltachain -m -Tjson
[
{
"chainid": 1,
"chainlen": 1,
"chainratio": 1.02325581395,
"chainsize": 44,
"compsize": 44,
"deltatype": "base",
"extradist": 0,
"extraratio": 0.0,
"lindist": 44,
"prevrev": -1,
"rev": 0,
"uncompsize": 43
}
]
Test max chain len
$ cat >> $HGRCPATH << EOF
> [format]
> maxchainlen=4
> EOF
$ printf "This test checks if maxchainlen config value is respected also it can serve as basic test for debugrevlog -d <file>.\n" >> a
$ hg ci -m a
$ printf "b\n" >> a
$ hg ci -m a
$ printf "c\n" >> a
$ hg ci -m a
$ printf "d\n" >> a
$ hg ci -m a
$ printf "e\n" >> a
$ hg ci -m a
$ printf "f\n" >> a
$ hg ci -m a
$ printf 'g\n' >> a
$ hg ci -m a
$ printf 'h\n' >> a
$ hg ci -m a
$ hg debugrevlog -d a
# rev p1rev p2rev start end deltastart base p1 p2 rawsize totalsize compression heads chainlen
0 -1 -1 0 ??? 0 0 0 0 ??? ???? ? 1 0 (glob)
1 0 -1 ??? ??? 0 0 0 0 ??? ???? ? 1 1 (glob)
2 1 -1 ??? ??? ??? ??? ??? 0 ??? ???? ? 1 2 (glob)
3 2 -1 ??? ??? ??? ??? ??? 0 ??? ???? ? 1 3 (glob)
4 3 -1 ??? ??? ??? ??? ??? 0 ??? ???? ? 1 4 (glob)
5 4 -1 ??? ??? ??? ??? ??? 0 ??? ???? ? 1 0 (glob)
6 5 -1 ??? ??? ??? ??? ??? 0 ??? ???? ? 1 1 (glob)
7 6 -1 ??? ??? ??? ??? ??? 0 ??? ???? ? 1 2 (glob)
8 7 -1 ??? ??? ??? ??? ??? 0 ??? ???? ? 1 3 (glob)
$ cd ..
Test internal debugstacktrace command
$ cat > debugstacktrace.py << EOF
> from mercurial.util import debugstacktrace, dst, sys
> def f():
> dst('hello world')
> def g():
> f()
> debugstacktrace(skip=-5, f=sys.stdout)
> g()
> EOF
$ python debugstacktrace.py
hello world at:
debugstacktrace.py:7 in * (glob)
debugstacktrace.py:5 in g
debugstacktrace.py:3 in f
stacktrace at:
debugstacktrace.py:7 *in * (glob)
debugstacktrace.py:6 *in g (glob)
*/util.py:* in debugstacktrace (glob)