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author | Roberto Ierusalimschy <roberto@inf.puc-rio.br> | 2022-05-20 13:14:33 -0300 |
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committer | Roberto Ierusalimschy <roberto@inf.puc-rio.br> | 2022-05-20 13:14:33 -0300 |
commit | 42d40581dd919fb134c07027ca1ce0844c670daf (patch) | |
tree | 9a1037510268dc09dbedebf2a91729399bcca2e0 /lvm.c | |
parent | e435aaabef8e717e0812a16a82b56acd11fb34c1 (diff) | |
download | lua-github-42d40581dd919fb134c07027ca1ce0844c670daf.tar.gz |
Save stack space while handling errors
Because error handling (luaG_errormsg) uses slots from EXTRA_STACK,
and some errors can recur (e.g., string overflow while creating an
error message in 'luaG_runerror', or a C-stack overflow before calling
the message handler), the code should use stack slots with parsimony.
This commit fixes the bug "Lua-stack overflow when C stack overflows
while handling an error".
Diffstat (limited to 'lvm.c')
-rw-r--r-- | lvm.c | 6 |
1 files changed, 4 insertions, 2 deletions
@@ -656,8 +656,10 @@ void luaV_concat (lua_State *L, int total) { /* collect total length and number of strings */ for (n = 1; n < total && tostring(L, s2v(top - n - 1)); n++) { size_t l = vslen(s2v(top - n - 1)); - if (l_unlikely(l >= (MAX_SIZE/sizeof(char)) - tl)) + if (l_unlikely(l >= (MAX_SIZE/sizeof(char)) - tl)) { + L->top = top - total; /* pop strings to avoid wasting stack */ luaG_runerror(L, "string length overflow"); + } tl += l; } if (tl <= LUAI_MAXSHORTLEN) { /* is result a short string? */ @@ -672,7 +674,7 @@ void luaV_concat (lua_State *L, int total) { setsvalue2s(L, top - n, ts); /* create result */ } total -= n-1; /* got 'n' strings to create 1 new */ - L->top -= n-1; /* popped 'n' strings and pushed one */ + L->top = top - (n - 1); /* popped 'n' strings and pushed one */ } while (total > 1); /* repeat until only 1 result left */ } |