Revision e6838a29ecb484c97e4efef9429643b9851fba6e authored by J. Bruce Fields on 21 April 2017, 20:10:18 UTC, committed by J. Bruce Fields on 25 April 2017, 20:34:37 UTC
A client can append random data to the end of an NFSv2 or NFSv3 RPC call without our complaining; we'll just stop parsing at the end of the expected data and ignore the rest. Encoded arguments and replies are stored together in an array of pages, and if a call is too large it could leave inadequate space for the reply. This is normally OK because NFS RPC's typically have either short arguments and long replies (like READ) or long arguments and short replies (like WRITE). But a client that sends an incorrectly long reply can violate those assumptions. This was observed to cause crashes. Also, several operations increment rq_next_page in the decode routine before checking the argument size, which can leave rq_next_page pointing well past the end of the page array, causing trouble later in svc_free_pages. So, following a suggestion from Neil Brown, add a central check to enforce our expectation that no NFSv2/v3 call has both a large call and a large reply. As followup we may also want to rewrite the encoding routines to check more carefully that they aren't running off the end of the page array. We may also consider rejecting calls that have any extra garbage appended. That would be safer, and within our rights by spec, but given the age of our server and the NFS protocol, and the fact that we've never enforced this before, we may need to balance that against the possibility of breaking some oddball client. Reported-by: Tuomas Haanpää <thaan@synopsys.com> Reported-by: Ari Kauppi <ari@synopsys.com> Cc: stable@vger.kernel.org Reviewed-by: NeilBrown <neilb@suse.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
1 parent 5a7ad11
decode_stacktrace.sh
#!/bin/bash
# (c) 2014, Sasha Levin <sasha.levin@oracle.com>
#set -x
if [[ $# < 2 ]]; then
echo "Usage:"
echo " $0 [vmlinux] [base path] [modules path]"
exit 1
fi
vmlinux=$1
basepath=$2
modpath=$3
declare -A cache
declare -A modcache
parse_symbol() {
# The structure of symbol at this point is:
# ([name]+[offset]/[total length])
#
# For example:
# do_basic_setup+0x9c/0xbf
if [[ $module == "" ]] ; then
local objfile=$vmlinux
elif [[ "${modcache[$module]+isset}" == "isset" ]]; then
local objfile=${modcache[$module]}
else
[[ $modpath == "" ]] && return
local objfile=$(find "$modpath" -name $module.ko -print -quit)
[[ $objfile == "" ]] && return
modcache[$module]=$objfile
fi
# Remove the englobing parenthesis
symbol=${symbol#\(}
symbol=${symbol%\)}
# Strip the symbol name so that we could look it up
local name=${symbol%+*}
# Use 'nm vmlinux' to figure out the base address of said symbol.
# It's actually faster to call it every time than to load it
# all into bash.
if [[ "${cache[$module,$name]+isset}" == "isset" ]]; then
local base_addr=${cache[$module,$name]}
else
local base_addr=$(nm "$objfile" | grep -i ' t ' | awk "/ $name\$/ {print \$1}" | head -n1)
cache[$module,$name]="$base_addr"
fi
# Let's start doing the math to get the exact address into the
# symbol. First, strip out the symbol total length.
local expr=${symbol%/*}
# Now, replace the symbol name with the base address we found
# before.
expr=${expr/$name/0x$base_addr}
# Evaluate it to find the actual address
expr=$((expr))
local address=$(printf "%x\n" "$expr")
# Pass it to addr2line to get filename and line number
# Could get more than one result
if [[ "${cache[$module,$address]+isset}" == "isset" ]]; then
local code=${cache[$module,$address]}
else
local code=$(addr2line -i -e "$objfile" "$address")
cache[$module,$address]=$code
fi
# addr2line doesn't return a proper error code if it fails, so
# we detect it using the value it prints so that we could preserve
# the offset/size into the function and bail out
if [[ $code == "??:0" ]]; then
return
fi
# Strip out the base of the path
code=${code//$basepath/""}
# In the case of inlines, move everything to same line
code=${code//$'\n'/' '}
# Replace old address with pretty line numbers
symbol="$name ($code)"
}
decode_code() {
local scripts=`dirname "${BASH_SOURCE[0]}"`
echo "$1" | $scripts/decodecode
}
handle_line() {
local words
# Tokenize
read -a words <<<"$1"
# Remove hex numbers. Do it ourselves until it happens in the
# kernel
# We need to know the index of the last element before we
# remove elements because arrays are sparse
local last=$(( ${#words[@]} - 1 ))
for i in "${!words[@]}"; do
# Remove the address
if [[ ${words[$i]} =~ \[\<([^]]+)\>\] ]]; then
unset words[$i]
fi
# Format timestamps with tabs
if [[ ${words[$i]} == \[ && ${words[$i+1]} == *\] ]]; then
unset words[$i]
words[$i+1]=$(printf "[%13s\n" "${words[$i+1]}")
fi
done
if [[ ${words[$last]} =~ \[([^]]+)\] ]]; then
module=${words[$last]}
module=${module#\[}
module=${module%\]}
symbol=${words[$last-1]}
unset words[$last-1]
else
# The symbol is the last element, process it
symbol=${words[$last]}
module=
fi
unset words[$last]
parse_symbol # modifies $symbol
# Add up the line number to the symbol
echo "${words[@]}" "$symbol $module"
}
while read line; do
# Let's see if we have an address in the line
if [[ $line =~ \[\<([^]]+)\>\] ]] ||
[[ $line =~ [^+\ ]+\+0x[0-9a-f]+/0x[0-9a-f]+ ]]; then
# Translate address to line numbers
handle_line "$line"
# Is it a code line?
elif [[ $line == *Code:* ]]; then
decode_code "$line"
else
# Nothing special in this line, show it as is
echo "$line"
fi
done
![swh spinner](/static/img/swh-spinner.gif)
Computing file changes ...